Lesson 22: Yitro

From the book Mida Tova: Articles on the Principles of Halakhic Thinking by Rabbi Michael Avraham. Translated from Hebrew using gpt-5.4 (reasoning_effort=high, batch API).

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With God’s help.

Concepts

• Logical negation and normative negation.
• A supportive commandment and a primary commandment.
• The relation between a distinction and the consequences derived from it.

Abstract

This week’s article deals with the relation between positive and negative commandments. At first glance, we are all accustomed to this distinction, and it seems very simple. But on closer inspection, a number of serious difficulties emerge. It is not clear what criterion determines when a given commandment is a positive commandment and when it is a negative one. We discuss the criterion of biblical wording—the way the commandment is formulated in Scripture—and the physical criterion—whether fulfillment requires active performance or passive abstention—and reject both.

Moreover, it seems that content does not dictate the character of a commandment at all, since there are positive commandments fulfilled through non-action, such as the prohibition of labor on the Sabbath, and negative commandments fulfilled through action, such as building a parapet. More than that, it is not at all clear how there can be an essential difference between a negative and a positive commandment, since every positive commandment can be reformulated as a negative one, and vice versa, by means of double negation: instead of commanding the laying of tefillin, one can forbid the state of being without tefillin; and instead of forbidding the eating of pork, one can command non-eating.

We show that these questions have implications for the enumeration of the commandments, and in their light we also discuss the views of the medieval authorities regarding women’s exemption from time-bound positive commandments that also have a parallel prohibition.

In the course of the discussion, we identify a common methodological error. Because of the difficulty just described, some seek to ground the basic distinction between positive and negative commandments in the very halakhic (Jewish legal) consequences of that distinction. We reject those proposals and show that the basis of the distinction must be logically prior to the consequences derived from it.

In the end, we propose a different criterion for distinguishing between positive and negative commandments. According to our proposal, the difference lies in whether the Torah points to a desired state or negates an undesired one. We then use logical analysis to explain why a negative formulation that employs double negation is not equivalent to the original positive commandment. This analysis sharpens the fundamental distinction between logical negation and normative negation. Logical negation operates on the truth-value of a proposition, whereas normative negation operates on the contents of the will—that is, on the norms themselves.

The Rules and Principles Arising from the Article

On the Relation between Positive and Negative Commandments¹

A Look at Logic and Halakha (Jewish law)

A. Between Positive and Negative Commandments

Introduction

In the Ten Commandments, the fourth commandment is the commandment of the Sabbath, in Exodus 20:8-11:

Remember the Sabbath day to sanctify it. Six days you shall labor and do all your work. But the seventh day is a Sabbath to the Lord your God; you shall do no work—you, your son or your daughter, your male servant or your female servant, your cattle, or the stranger who is within your gates. For in six days the Lord made heaven and earth, the sea and all that is in them, and He rested on the seventh day; therefore the Lord blessed the Sabbath day and sanctified it.

Within this passage appear both the positive commandment of “Remember the Sabbath day to sanctify it” and the negative commandment of “You shall do no work.” In the parallel passage in Va’ethanan, the positive commandment appears in different language: “Observe the Sabbath day,” and the Sages explain that there it refers to the negative commandment.²

Nahmanides, in his commentary here, discusses the relation between positive commandments and prohibitions. In our article on Vayetzei, 2006-2007, we cited his words in a discussion of logical loops in halakha. Here we will examine them from a different angle.

Let us cite the passage in Nahmanides that concerns the relation between positive and negative commandments:

It is also true that the aspect of “remember” is hinted at through a positive commandment, and it derives from the attribute of love and belongs to the attribute of mercy. One who performs his master’s commandments is beloved to him, and his master has mercy upon him. The aspect of “observe” is through a negative commandment, and it belongs to the attribute of judgment and derives from the attribute of fear. One who guards himself from doing what is evil in his master’s eyes fears him. Therefore a positive commandment is greater than a negative commandment, just as love is greater than fear. For one who fulfills and does his master’s will with his body and his money is greater than one who merely guards himself from doing what is evil in his eyes. Therefore they said that a positive commandment comes and overrides a negative commandment. And for this reason the punishment for a negative commandment is greater, and punishment is administered for it, such as lashes and death, whereas no punishment at all is administered for a positive commandment except in the case of rebels—for example: “I will not take a lulav,” “I will not make fringes,” “I will not build a sukkah”—for then the Sanhedrin would strike him until he accepted upon himself to perform it, or until his soul departed.

Positive commandments derive from love and mercy, whereas negative commandments derive from fear. Positive commandments are the doing of what the Holy One wants out of love for Him, whereas negative commandments are the guarding of oneself against failure in matters He does not want us to do. From this Nahmanides concludes that just as love is greater than fear, so positive commandments are greater than prohibitions. From here he infers that a positive commandment overrides a negative one. On the other hand, the punishment for transgressing a negative commandment is greater than for neglecting a positive one; in practice, neglect of a positive commandment is not punishable by a court at all.

In this same discussion, Nahmanides also mentions the rabbinic teaching that women are obligated in the positive commandment of the Sabbath, even though it is time-bound, because they are obligated in the Sabbath prohibition, and “remember” is juxtaposed to “observe,” the two having been uttered in one utterance.

The Author of Tanya in Iggeret HaTeshuvah

As we mentioned in our article on Toledot, 2006-2007, Nahmanides points there to apparent contradictions in the halakhic status of positive and negative commandments. On the one hand, a positive commandment overrides a negative commandment. On the other hand, for a positive commandment one must spend only up to one-fifth of one’s assets, and there is no punishment for failing to fulfill it, whereas for a negative commandment one must spend all one’s assets to avoid transgressing it, and violation is punishable. As we saw, the basis of his position is that fulfilling a positive commandment is greater than refraining from violating a prohibition, but neglecting a positive commandment is lighter than violating a prohibition.

One of our readers drew our attention to the words of the author of Tanya, in chapter 1 of Iggeret HaTeshuvah, who also addresses this question and writes as follows:

It is taught at the end of tractate Yoma: there are three categories of atonement, and repentance accompanies each one. If one transgressed a positive commandment and repented, he does not move from there until he is forgiven. If one transgressed a negative commandment and repented, repentance suspends the punishment and Yom Kippur atones.

This means that although, with respect to the fulfillment of a positive commandment, it is greater, in that it overrides a negative commandment, that is because by fulfilling a positive commandment one draws down light and abundance into the higher worlds from the radiance of the light of the Infinite One, blessed be He—as is written in the Zohar that the 248 commandments correspond to the 248 limbs of the King—and also into one’s divine soul, as we say: “who has sanctified us with His commandments.” But regarding repentance, even though one is forgiven the punishment for rebelling against His kingdom and not carrying out the King’s command, nevertheless the light is absent, etc.; as the Sages said on the verse “That which is crooked cannot be made straight”: this refers to one who neglected the evening Shema or the like. For even if from now on he is careful to recite the evening and morning Shema forever, his repentance cannot repair what he once neglected.

One who transgresses a negative commandment, by causing evil to cling to his soul, creates a blemish above in the root from which his soul was hewn—in the garments of the ten sefirot of the world of Asiyah, as is explained in Tikkunei Zohar: “You made garments for them, from which souls fly to human beings,” etc. Therefore there is no atonement for his soul, nor above, until Yom Kippur, as it is written: “He shall make atonement for the Sanctuary because of the impurities of the children of Israel and because of their transgressions… Before the Lord you shall be purified”—precisely “before the Lord.”

Therefore one must not infer from this, Heaven forbid, any leniency regarding positive commandments, and especially not regarding Torah study. On the contrary, the Sages said that the Holy One, blessed be He, overlooked idolatry and the like, though these incur excision and death by the court, but did not overlook neglect of Torah study.

If one transgressed sins punishable by excision or by death at the hands of the court, repentance and Yom Kippur suspend the punishment, and sufferings cleanse completely. That is, they complete the atonement; the word is related to rinsing and washing, to polish the soul. For atonement is an expression of wiping away, which wipes away the filth of sin. As it is said: “I will punish their transgression with the rod and their iniquity with blows.”

The author of Tanya argues that although there is no punishment for a positive commandment and there is punishment for a negative commandment, the reason is not that the positive commandment is lighter. Quite the contrary: punishment cannot repair the neglect of a positive commandment, because the absence of light caused by that neglect remains. Punishment can atone only for violation of a negative commandment, because it cleanses the spiritual filth produced by the sin. Violation of a prohibition creates a kind of spiritual contamination that punishment can remove. Neglect of a positive commandment, by contrast, causes an absence of light, and no punishment can repair that. According to him, then, the positive commandment is more severe across the board.

B. Difficulties in Defining Positive and Negative Commandments

Introduction

Until now we have assumed that positive and negative commandments are well defined, and the question before us was what the correct halakhic relation between them is: which is more severe, and with what legal consequences. In this chapter we will see that the very definitions of positive and negative commandments are problematic, both logically and normatively.

The Uniqueness of the Sabbath: A First Look at the Basic Difficulties

We saw above that the Sabbath commandment includes both a positive commandment and a negative commandment. Let us emphasize that these two commandments have the same normative content: both forbid the performance of labor—the thirty-nine primary categories and their derivatives—on the Sabbath.³

This sharpens a very basic difficulty in the relation between positive commandments and prohibitions. First, let us ask ourselves: what exactly is the difference between a positive commandment and a prohibition? Seemingly, a positive commandment orders us to get up and do something—such as to lay tefillin, attach fringes to a garment, recite grace after meals, honor parents, and the like—whereas a prohibition warns us not to do an act—such as the prohibition of eating pork or of wearing garments of mixed wool and linen.

In standard halakhic terminology, one would say that a positive commandment imposes an obligation of active performance, whereas a negative commandment imposes an obligation of passive abstention.

But precisely in light of this sharp distinction, a question arises: how can there be overlap in content between a positive commandment and a negative one? If the obligation imposed by a positive commandment is active performance, and the obligation imposed by a negative commandment is passive abstention, how can both impose exactly the same obligation, as in the case of the Sabbath?

To sharpen the point: the Sabbath commandment should seemingly have been a negative commandment, since it forbids us to do labor. The duty imposed upon us is one of abstention, not action. A further question therefore arises: how is “remember” defined at all as a positive commandment rather than a prohibition, if it imposes on us a duty of abstention? This is a different question from the previous one. Even if there were no negative commandment here at all—namely “observe”—it would still not be clear how “remember” can be defined as a positive commandment. So there are really two questions: the question of duplication and the question of the definition of the commandment of “remember.”

To sharpen this further, let us suggest a common explanation of the essence of “remember.” Many explain that what is imposed upon us is not merely a duty not to do labor on the Sabbath, but a duty to rest on the Sabbath. The duty to rest is something like an active obligation, and therefore it is defined as a positive commandment rather than a prohibition. But even before we examine this explanation more closely, it resolves only the second difficulty. The difficulty of duplication remains intact. If the duty on the Sabbath is indeed to rest, then “observe” should also have been a positive commandment. Following that line, we would apparently have to say that there are two different commandments here: to rest, as an active obligation, and to refrain from doing labor, as an abstentive obligation. On that view, both difficulties would seemingly be resolved.

The Essential Difficulty

But the essential difficulty remains. If a positive commandment can indeed contain content that, in practical terms, imposes on me an obligation of abstention, then the question returns: what, exactly, is the difference between positive commandments and prohibitions?

Let us present the difficulty differently. If the Torah had commanded me not to remain without tefillin, this would apparently have been a negative commandment rather than a positive one. But its practical content would have been identical to the positive commandment to put on tefillin. So what is the difference between a positive commandment and a prohibition? When does the Torah define a certain duty as a prohibition, and when as a positive commandment? If the practical criterion does not define the relation between the two, what criterion does?

The question can be put differently still: what would change if the Torah had imposed upon us not a prohibition concerning Sabbath observance but only a positive commandment, or vice versa? Our practical obligations would apparently look exactly the same.

Some may wish to answer that the difference lies in the legal consequences. For example, if there is a prohibition here, then women are obligated in it; if it is a positive commandment, then they are exempt, because it is time-bound. Or, if there is a prohibition, then we must spend all our wealth in order to avoid violating it, whereas if it is a positive commandment, then we are obligated to spend only up to one-fifth of our assets. Perhaps there is also a difference in the laws of doubtful cases, and so on. There are even leniencies generated by the positive commandment. For example, if Sabbath observance conflicts with another prohibition, then because the Sabbath also has a positive commandment, it will override that prohibition. If it were only a prohibition and not also a positive commandment, there would be no such override.

But none of this helps us here. All these are halakhic consequences that result from the fact that we are dealing with a prohibition rather than a positive commandment. Our question, however, is in what sense the prohibition differs from the positive commandment. What is the factor that gives positive and negative commandments different definitions and different laws? The consequences cannot define the difference itself, when they are only its results.

More concretely: what makes us violate one prohibition in order to preserve the Sabbath, because a positive commandment overrides a negative one? The fact that the Sabbath includes a positive commandment and not only a prohibition seems, in itself, to reflect nothing essential. The duty imposed upon us on the Sabbath is, ostensibly, a duty of abstention, and such duties do not override prohibitions. So what is there in a positive commandment that is not in a prohibition, beyond a semantic definition? When does the Torah define the obligation as a duty to put on tefillin, and when as a duty not to be without tefillin?

An Implication for the Enumeration of the Commandments

Maimonides, in the Ninth Root, writes that duplicate commandments are not counted separately. If a commandment is repeated several times in the Torah, it is counted in the enumeration of the commandments only once. We mentioned above that one of his examples is Sabbath observance, which is mentioned in the Torah twelve times yet counted only once.

But in the Sixth Root Maimonides qualifies this principle and determines that if, on the same subject, there is both a positive commandment and a negative commandment, we count both in the enumeration. Again, one of the examples is the Sabbath: both the prohibition—“observe”—and the positive commandment—“remember”—are counted in Maimonides’ enumeration.

This shows that duplication between a positive commandment and a negative one differs from duplication between two positive commandments or two negative ones. Two prohibitions or two positive commandments are mere repetition. Maimonides explains there that the repetition is intended to emphasize the severity of the offense, while Nahmanides, in his glosses there, disputes him on that point. But if the duplication is between a negative commandment and a positive one, then there must apparently be some essential difference between them, and that is why both are counted in the enumeration. Yet in all the relevant cases, the positive and the negative commandment have overlapping content, as in the case of the Sabbath; otherwise the entire discussion would not arise. So what is the difference that causes the positive and the negative commandment to be counted rather than treated as duplicates?

Rabbi Yeruham Fishel Perla, in his introduction to Saadia Gaon’s Sefer HaMitzvot on the Sixth Root, argues that Saadia Gaon disagrees with Maimonides on this point, and indeed does not count a positive and a negative commandment separately. From his standpoint, duplication between a positive and a negative commandment is exactly like duplication between two positive commandments or two prohibitions. Which of the two, then, is counted? Presumably the commandment whose character fits the practical content of the command. Yet it may not necessarily be the practical character of the commandment so much as its more essential content. For example, in Sabbath observance the practical content is abstention from labor, but Saadia nevertheless counts it specifically as a positive commandment rather than a prohibition.

Sharpening the Question

What, then, is Maimonides’ view on this matter? How does he distinguish in an essential way between a negative commandment and a positive one when both have the same normative content? If the distinction is not based on active performance as opposed to passive abstention, what is the principled distinction between them?

At first glance, the words of the author of Tanya cited above offer a possible explanation. The aim of a positive commandment is to increase light, whereas the concern of a negative commandment is to prevent spiritual filth in the soul. But this distinction, too, does not directly answer our question. The issue with which we are concerned lies wholly within the normative sphere. We are asking what the categorical halakhic difference is between a positive and a negative commandment, not what the metaphysical difference is. The fact that some actions add light and others produce “filth” does not help us understand their legal significance. Why, in fact, does keeping the Sabbath add light, or prevent filth? And in general, how do we determine which acts add light and which create filth? On the face of it, this ought to have some connection with the concepts of active performance and passive abstention, given that the very terms are “do” and “do not do.” Yet at the halakhic level, it does not seem to work that way at all.

C. Kiddushin 34a: Women’s Obligation in the Law of a Parapet

Introduction

The Gemara in Babylonian Talmud, Kiddushin 34a, lists the time-bound positive commandments and those that are not time-bound:

The Rabbis taught: Which are the positive commandments that are time-bound? Booth, palm branch, ram’s horn, fringes, and tefillin. And which are the positive commandments that are not time-bound? Mezuzah, parapet, lost property, and sending away the mother bird.

Tosafot, s.v. “Parapet,” and several other medieval authorities there, raise the following difficulty:

Parapet, lost property, and sending away the mother bird—this is difficult for Rabbi, for in all of these a prohibition is also written. With regard to parapet it is written, in Deuteronomy 22, “Do not place blood in your house.” Although we establish it in Babylonian Talmud, Bava Kamma 15b, as applying to one who keeps a vicious dog or a broken ladder—that is, placing danger there by hand—still it also applies to parapet, for in the halakhic midrash Sifrei they expound: “You shall make”—this is a positive commandment; “Do not place blood”—this is a negative commandment. Regarding lost property too it is written, in Deuteronomy 22, “You may not hide yourself,” and regarding sending away the mother bird it is written there, “You may not take the mother with the young.” If so, how could women be exempt even if these were time-bound? Does not Scripture equate woman and man with respect to all punishments in the Torah?

The difficulty is why parapet is included in the list at all. This commandment, like several others in the list, includes a prohibition as well. If so, women would be obligated in it even if it were time-bound.

At first glance, this may seem to be a technical discussion about women’s exemption from certain commandments. But we will see below that fundamental conceptions of the relation between positive and negative commandments emerge in the course of the discussion.

Tosafot’s Approach

Tosafot resolves the difficulty as follows:

Rabbi Isaac says that in all of them one can find cases of the positive commandment without the prohibition. In the case of parapet, “Do not place blood” applies only when one builds a house from the outset with the intention of not making a parapet. But if he intended to make a parapet and, after building, changed his mind, or if he made one and it fell, then there remains only the positive commandment of “You shall make a parapet,” and then women would be exempt.

Tosafot thus finds itself compelled to distinguish between the positive commandment and the prohibition, and to show that their practical and normative contents differ. The reason is not the logical problem raised here, but a technical one concerning women’s exemption. Tosafot does not appear bothered by the duplication as such, that is, by the fact that the two have the same practical content.

There is an interesting remark here by the author of Pnei Yehoshua, who says that were it not for Tosafot’s words, he would have explained that the difference between the positive commandment and the prohibition is that in the case of a positive commandment there is greater value in performing it oneself than through an agent. In other words, if making a parapet is a positive commandment, then there is value in doing it ourselves. But if it is only a prohibition, then there is no special value in making the parapet at all, and certainly not in doing so ourselves. What is required of us is merely to ensure that the roof not remain without a parapet.

His point is that even if there is no difference in content between the positive commandment and the prohibition, there are legal consequences to their classification as positive or negative. Therefore Tosafot’s question is not difficult. If parapet were time-bound, women would indeed have to ensure that the roof not remain without a parapet, but they would not be obligated to do this themselves. The Gemara, in saying that parapet is not time-bound, would then be telling us that women too are obligated to build the parapet themselves.

It should be noted that Pnei Yehoshua assumes that there is no practical distinction at all between the content of the positive commandment and that of the prohibition, and yet he claims there is still a legal consequence to defining the commandment one way or the other. This, of course, greatly sharpens the difficulties we raised in the introduction.

Further on, Tosafot offers another explanation of the difficulty:

Others explain that there is nevertheless a practical difference when a woman has another positive commandment to fulfill. For had we said that women are exempt from the positive commandment that is not time-bound, they would likewise be exempt from the prohibitions that accompany it, since one could say that a positive commandment comes and overrides a negative commandment. But when they are obligated in the positive commandment that is not time-bound, then another positive commandment will not come and override it, for a positive commandment does not override both a negative commandment and a positive commandment.

Tosafot thus raises the possibility that even though parapet includes a prohibition, it is still important to teach that women are not exempt from the positive commandment. The practical consequence appears in a situation where another positive commandment conflicts with the commandment of parapet. In such a case, if women were exempt from the positive commandment because it is time-bound, there would remain only a prohibition. If so, the conflicting positive commandment should override it. By contrast, with respect to men, the positive commandment would not override the commandment of parapet, because for them both a prohibition and a positive commandment are present.

This is similar to the remark from Pnei Yehoshua cited above. But according to this view in Tosafot, no separate legal difference between the positive commandment and the prohibition is required. The difference will arise only in situations where this commandment conflicts with another positive commandment, and the question is whether it is overridden or not.

The situation in which this position would find expression is described later in Tosafot, in Rabbi Yosef of Eretz Israel’s objection to the approach described above:

Rabbi Yosef of Eretz Israel objected to this explanation: if so, with regard to the rule that one may not light with oil of impure terumah designated for burning on a Festival, because a Festival has both a positive and a negative commandment, whereas the burning of consecrated items is only a positive commandment—would it then follow that a woman, who is not obligated in the Festival positive commandment because it is time-bound, may light with such burning oil on a Festival? And if you say yes, why did no tanna ever mention this?

The case of burning impure terumah on a Festival is precisely the case described above. There is a positive commandment to burn the impure terumah, and opposite it stands the prohibition of labor on a Festival, which consists of both a negative commandment and a positive one. According to Tosafot’s proposal, women should be able to burn consecrated foods such as impure terumah on a Festival, since labor on a Festival is prohibited to women only by a prohibition and not also by a positive commandment, because the positive commandment is time-bound and women are exempt from it. Rabbi Yosef’s objection is that we do not find any decisor, either in the Talmud or afterward, who permits this for women. He therefore rejects the proposal and says:

Rather, what must you say? A positive commandment that is accompanied by a prohibition renders even the prohibition itself stronger, so that a positive commandment does not override it. Here too, the prohibition is stronger.

Rabbi Yosef argues that when a prohibition comes together with a positive commandment that overlaps it in content, the prohibition itself becomes more severe. Such a prohibition is not set aside by a positive commandment. This, he suggests, explains why even women are forbidden to burn impure terumah on a Festival. According to this, Tosafot’s proposal just cited must be rejected, since even if the prohibition and the positive commandment in parapet overlap in content, the presence of the positive commandment strengthens the force of the prohibition, and another positive commandment will not override it.

How are we to understand the claim that the presence of the positive commandment strengthens the prohibition? Why should that happen? At first glance, the opposite would seem more plausible: if a positive commandment has to be added, then the prohibition by itself must be weak.

It appears that Rabbi Yosef holds that the prohibition and the positive commandment are not counted as two separate commandments. The very presence of these two formulations in the Torah indicates that the Torah views this prohibition as especially severe. It is counted only as a prohibition, but it is a more severe prohibition because it was emphasized twice; therefore it is not overridden by another positive commandment. If so, Rabbi Yosef seems to assume that a prohibition and a positive commandment are indeed ordinary duplication, like two prohibitions or two positive commandments. And as we saw in Maimonides’ Ninth Root, ordinary duplication indicates greater severity but is certainly not counted as two separate commandments.

According to Rabbi Yosef, then, Tosafot’s second explanation is rejected, and we must return to the first explanation, according to which there is a practical difference in content between the positive commandment and the prohibition. But whereas for Tosafot the basis of that explanation was technical, in order to explain women’s exemption, for Rabbi Yosef it seems to rest on principle: if there were complete overlap in content, there would not be two commandments here at all, but one severe commandment.

Comparison to the View of Saadia Gaon

It seems from his words that this single commandment would be counted, in his view, as a prohibition rather than a positive commandment—he calls it a strong prohibition. Why does he choose to count it specifically as a prohibition? It seems that he agrees with Saadia Gaon that one should count the commandment that fits the substantive character of the command. But it should be noted that with regard to Festivals, where in his view the content really does overlap, he counts specifically the prohibition and not the positive commandment. This is unlike Saadia Gaon, who, as we saw above, counts the Sabbath and Festivals specifically as positive commandments.

So there is a position here that resembles Saadia Gaon in one respect and differs from him in another. Rabbi Yosef agrees with Saadia Gaon that a positive commandment and a prohibition with overlapping content constitute ordinary duplication, unlike Maimonides, and therefore only one of them should be counted. But according to Saadia Gaon, as we saw, the count is not determined solely by the practical content of the commandment, for on the Sabbath the practical content is abstention and yet Saadia counts it as a positive commandment. On that point Rabbi Yosef differs from him. In Rabbi Yosef’s view, what determines the matter is only the practical character of the commandment: a positive commandment is one of active performance, and a prohibition is one of abstention.

Nahmanides’ Approach: A Prohibition That Supports a Positive Commandment

Nahmanides, and likewise Ritva on this passage, cites Tosafot’s difficulty and rejects the solution. He then offers his own alternative:

It seems to me that its principal commandment is the positive one, and the prohibition in it exists only to sustain the positive commandment. For Scripture wrote first “You shall make a parapet,” and afterward “You shall not place blood in your house”—that is, do not delay in performing this commandment. This is a prohibition that contains no act other than the fulfillment of the positive commandment within it. Were women exempt from the positive commandment, they would be exempt from the prohibition as well, since the prohibition is only the maintenance of the positive commandment. But with other positive commandments that also contain both a prohibition and a positive commandment, women are obligated in both, as we say in Babylonian Talmud, Shabbat 24b and Beitzah 8b: “Rest” is a positive commandment, and a positive commandment does not come and override both a negative commandment and a positive commandment; and man and woman are equal in this matter.

Nahmanides explains that if parapet had been a time-bound positive commandment, women would have been exempt from it even though there is also a parallel prohibition. The reason is that in parapet the duplication is essential, unlike the Sabbath and Festivals. In the case of parapet, the prohibition is only a supporting wall for the positive commandment, intended to ensure that we perform it. In such a case, if women were exempt from the positive commandment, they would also be exempt from the prohibition. In other words, the existence of the prohibition does not make the Gemara’s novelty—that women are obligated in the positive commandment of parapet—superfluous.

Nahmanides can be understood in two ways:

1. We mentioned above that in the Ninth Root Nahmanides is unwilling to accept ordinary duplication in the Torah. In his view, even where the Torah repeats the same command, whether positive or negative, it intends thereby to teach something additional. If so, in any case where we see complete duplication, there must be some difference in content. And if we do not find such a difference, then one side is intended to support the other and is not counted as a separate commandment at all. On this understanding, the prohibition here is nothing other than the positive commandment phrased differently, and women would therefore be exempt from it as well.

This direction is problematic. First, why does Nahmanides choose the positive commandment rather than the prohibition as the primary one? Second, with regard to the Sabbath and Festivals he does accept the duplication of a prohibition and a positive commandment, so what is different about parapet?

2. Alternatively, the positive commandment and the prohibition are indeed two commandments. A prohibition that supports a positive commandment is still a prohibition, but in essence it is a special kind of prohibition whose entire function is to support the positive commandment. On this view, we can understand that even if there are indeed two commandments here, women would still be exempt from both. For if they were exempt from the positive commandment, why should they be obligated in the prohibition? The whole point of the prohibition is to ensure that the positive commandment is performed; where there is no positive commandment, there is nothing for it to support.

The difference between these two understandings concerns, of course, the question whether one who violates the law of parapet violates both a prohibition and a positive commandment, or only a positive commandment. In practice, however, the differences are slight, if they exist at all. Almost all the ordinary differences between positive commandments and prohibitions would not find expression here.

For example, how much money would we have to spend in order not to violate the law of parapet? Presumably only one-fifth, since the goal is to fulfill the positive commandment, and the prohibition is there only to ensure that we do so. One might, however, argue the opposite: precisely for that reason the Torah added a prohibition here, to teach us that in the case of parapet we must spend all our money. But in terms of the essence of the prohibition, that is difficult to accept, for the prohibition here is, in essence, a positive commandment—or support for a positive commandment—and it is not clear why mere wording by the Torah should change that. As we saw above, wording in the Torah is not a sufficient explanation for defining something as a prohibition; there must be some underlying normative basis.

What about punishment? The same considerations would apparently arise here as well. On the one hand, positive commandments are not punishable, so it is hard to see how we could punish for the prohibition, whose entire function is only to serve as a support for the positive commandment. The wording in which the command was stated cannot by itself provide a sufficient basis for such punishment.

Application to Feeding Minors on Yom Kippur

The author of Dibrei Yehezkel, section 15, subsection 18, applies Nahmanides’ reasoning in another legal context. Many commentators ask how it can be permitted to feed minors on Yom Kippur, given that there is a prohibition against directly causing a minor to consume forbidden food, derived from the verse “you shall not eat them,” interpreted as “you shall not cause them to be eaten”; see Babylonian Talmud, Yevamot 113a.⁴ Some explain this on grounds of danger to life, but that is puzzling.

The author of Dibrei Yehezkel cites views among the decisors that the prohibition against directly feeding a minor forbidden food applies only to prohibitions and not to positive commandments. He then continues: the prohibition of eating on Yom Kippur is intended to support the positive commandment of self-affliction, and therefore in this case it is permitted to feed minors and thereby transgress even the prohibition.

A Further Look at Nahmanides

In the end, we must ask ourselves why Nahmanides decided that in the case of parapet the positive commandment is primary rather than the prohibition. Why did he not determine, instead, that the positive commandment is what supports the prohibition? We must also ask why, with regard to the Sabbath, he does not say something similar. Why, according to his view, are women there obligated?

Apparently, with respect to the Sabbath and Festivals, Nahmanides sees the prohibition as primary and the positive commandment as secondary, and therefore women are obligated in them. By contrast, in parapet the positive commandment is primary, and therefore if it were time-bound women would be exempt. In parapet it is fairly clear why the positive commandment is primary, since the command is that we rise and do something—namely build a parapet. In the Sabbath, by contrast, the essence is that we not perform labor, and therefore there the prohibition is primary.

It should be emphasized that Nahmanides does not make this distinction with respect to the enumeration of the commandments, as Saadia Gaon or Rabbi Yosef of Eretz Israel does. He explicitly writes, in his glosses to the Sixth Root, that he agrees with Maimonides that the positive commandment and the prohibition should be counted separately. His claim here concerns only which of the two is primary and which secondary, and the consequence is with respect to women’s exemption. In parapet, if it were time-bound, there would indeed be two commandments—not like Saadia Gaon—but women would be exempt from both. By contrast, in the Sabbath and Festivals, which are time-bound, there are indeed two commandments—again, not like Saadia Gaon—but women are obligated in both.

D. The Solution: Between Normative Negation and Logical Negation

Back to the Basic Question of the Relation Between Positive and Negative Commandments

Nahmanides’ words sharpen with even greater force the basic difficulty we raised above. If the content of the positive commandment and the prohibition, both in the Sabbath and Festivals and in parapet, overlaps, then in what sense do we have here a prohibition and a positive commandment? We can ask further: in what sense does the prohibition of “Do not place blood in your house” support the positive commandment of parapet? What is present in the prohibition that is absent from the positive commandment—especially against the background of Nahmanides’ own statement that there is nothing in it beyond the positive commandment, since its entire purpose is support? Precisely because of that support, Nahmanides concludes that this prohibition involves no greater stringency than the positive commandment. So why, and in what sense, does the existence of a prohibition strengthen the positive commandment?

This returns us to the general questions presented in the previous chapter: what really is the difference between a positive commandment and a prohibition? Why is the command to keep the Sabbath different from the command not to desecrate the Sabbath, when the content of the two commands is completely identical?

The Logical Problem

The question can be presented as a logical problem. Seemingly, a double application of logical negation leads us back to the same result. If so, when the Torah commands us not to be without tefillin, that is exactly like a command to be with tefillin. The opposing prohibition and positive commandment therefore necessarily have the same practical content, and so they would appear to be one and the same commandment in two formulations.

Grounding a Distinction in Its Own Consequences

Aharon Shemesh, in his article “Toward a History of the Meaning of the Concepts Positive Commandment and Negative Commandment,”⁵ distinguishes between those who define positive and negative commandments linguistically, by the Torah’s mode of formulation, and those who define them performatively, by the mode of fulfillment or transgression—passive abstention as opposed to active performance. But it is clear that neither distinction is sufficient, as we shall now see.

As for the practical distinction, at least according to Maimonides, who counts a positive commandment to rest—that is, not to perform labor—on the Sabbath, it is obvious that this cannot provide the criterion that distinguishes between a positive commandment and a prohibition. Even Saadia Gaon, who in the case of the Sabbath counts only one commandment, counts it specifically as a positive commandment and not as a prohibition. That is, even in his view practical character is not what determines the matter.

Nahmanides, as we saw above, does differ from Saadia Gaon with respect to the duplication between a prohibition and a positive commandment. But he defines the primary and the secondary between them according to practical character. He holds that in parapet the positive commandment is primary because the goal is the making of the parapet, and that is the duty imposed upon us. In the Sabbath and Festivals, by contrast, the prohibition is primary because the duty imposed upon us is abstention. Yet Nahmanides does not classify prohibitions and positive commandments on that basis, for he does not dispute the fact that in the Sabbath and Festivals there is both a prohibition and a positive commandment, and likewise in parapet. His discussion concerns only which of them is primary. He is willing to accept a prohibition that imposes an obligation to do something actively, as in parapet, and a positive commandment that commands one not to do something, as in the Sabbath.

It is true that according to our suggestion above regarding the view of Rabbi Yosef of Eretz Israel, the criterion may indeed be the practical one, but this is a lone view, and even there it is not explicit.

What, then, of the linguistic distinction? One might perhaps say that a positive commandment is one that the Torah formulates as a positive commandment, that is, as an active directive, whereas a negative commandment is one formulated as a duty of abstention. Could that be the criterion distinguishing between them?⁶ Certainly not, for two main reasons:

1. As we have seen, at the logical level these formulations are equivalent. It cannot therefore be the formulation itself that constitutes the distinction between these kinds of commandments.
2. A linguistic-semantic distinction cannot serve as a logical foundation for an essential distinction, because it merely reflects the existence of the distinction; it does not constitute it. Because certain commandments have the character of positive commandments, they are formulated linguistically as positive commandments, and likewise with prohibitions. The question is: what is that character that distinguishes the two types? The wording is an expression of the difference, not the difference itself.

An Example: Lesser Sacrifices

Because this type of error is common, let us dwell on it a little longer. We have seen here several attempts to ground an essential distinction in its consequences: either the legal consequences, that is, the laws governing positive and negative commandments, or the semantic ones, that is, the form of their formulation. As we argued above, one cannot ground an essential distinction in the consequences that flow from it. It is crucial to distinguish between the reasons for a distinction and the results derived from it.

As is well known, there is a dispute whether lesser sacrificial offerings are the property of their owners or the property of Heaven. One must understand in what sense lesser sacrificial offerings can be the property of their owners, given that they are consecrated and designated only for sacrifice. In that respect they are like the most sacred offerings.

Some commentators point, by way of explanation that they are the owner’s property, to the fact that one can betroth a woman with them, by giving her something of value consisting of a lesser sacrificial offering, and the like. But the fact that one can betroth a woman with them is not the reason they are defined as the owner’s property; it is a consequence of that definition. One cannot cite the possibility of betrothal as the explanation or constitutive basis of something’s being someone’s property. There must obviously be some meta-legal explanation that defines the nature and type of ownership and explains why this is not absolute sanctity. The ability to betroth a woman with it is only a result of that explanation.

Defining positive commandments through their character as obligations of active performance, if that were correct, would indeed be a good definition. It would provide a meta-halakhic basis for the legal-normative differences. The legal consequences themselves would not be serving as the basis of the distinction; rather, they would flow from it. The Torah’s wording too would be a result of that distinction, not its constitutive ground. But as we have seen, according to most of the medieval authorities this definition is not correct, and therefore we must seek another essential definition that will give us a criterion for distinguishing between positive and negative commandments.

Our Proposed Criterion for Distinguishing Positive and Negative Commandments

From all the considerations raised thus far, it emerges that a positive commandment is an expression of the Torah’s positive will, whereas a prohibition is an expression of negative will. For example, the command to make a parapet is an expression of the will to arrive at a certain state: that the roof have a parapet. When the Torah points to what it wants, that is a positive commandment. By contrast, the command “Do not place blood in your house” means that the Torah does not want there to be a state in which a dangerous obstacle exists in my home. This is an expression of will with respect to a state undesirable to the Torah, and therefore it is a prohibition and not a positive commandment.

We can now understand that the distinction between positive and negative commandments is not connected to the question whether I am required to perform an active action or am required not to perform one. Let us examine this by means of the two exceptional examples cited above: the Sabbath, where we have a positive commandment that finds practical expression through abstention, and parapet, where we have a prohibition that finds practical expression through action. We can now see how the definition we have proposed explains both phenomena.

The commandment to rest on the Sabbath should, on our account, be understood as an expression of the will that I be in a state of rest on the Sabbath, and therefore it is a positive commandment. The Torah says here what it wants to exist, not what it does not want to exist. Even though there is no instruction here to perform any particular action, pointing to a desired state is a positive commandment. By contrast, the command “You shall do no work” expresses the will that there not be a state in which I perform labor on the Sabbath. Since it points to an undesirable state, it is a prohibition.

Exactly the opposite occurs in the commandment of parapet. There we encounter a prohibition whose purpose is to motivate me to perform an action—namely, to build a parapet. The reason this instruction counts as a prohibition is that the Torah here negates an undesirable state rather than pointing to a desirable one. From the standpoint of the prohibition, the act of building the parapet is not really what is demanded of me. The action is meant to prevent a state in which the Torah is not interested—that my house be without a parapet, that is, that bloodguilt be in it. The positive commandment, by contrast, is an instruction to build a parapet; here the Torah points to what it wants rather than what it does not want, and therefore it is a positive commandment rather than a prohibition.

Explaining the Consequences: The Semantic and the Halakhic

Above we saw that some tried to ground the distinction between positive and negative commandments in the consequences of that distinction, and we pointed out the difficulty in such approaches. We can now travel in the opposite direction: from the basic definition, we can understand the consequences, both semantic and halakhic.

At the semantic level, positive commandments are usually formulated as active directives and prohibitions as abstentive directives. But that is not the basic definition of positive and negative commandments; it is only their verbal expression. When the Torah formulates something as a positive commandment, it is not necessarily telling us to do something. It means to teach that the positive state is the one it desires. Conversely, when it formulates something as a prohibition, its intention is to indicate an undesirable state and negate it. Sometimes active behavior is required in order not to find oneself in that state, and the commandment will still be a prohibition.

At the halakhic level, we saw that Nahmanides explains that the Torah wrote a prohibition in the case of parapet in order to strengthen the positive commandment, and that this has legal consequences as well. We asked: in what sense does such a prohibition strengthen the positive commandment? What is the difference between forbidding us to leave the roof without a parapet and positively instructing us to build one?

The answer is that this is a kind of “stick” and “carrot.” If there were only a positive commandment to build a parapet, we might think that it is possible not to build one without thereby violating the Torah’s will. Failure to build does not clash head-on with the Torah’s will, because the resulting state—that my roof has no parapet—is not, in the positive commandment alone, defined as a state undesirable to the Torah. In the positive commandment, the Torah pointed to a desirable state, or more precisely to a desirable action: that I build a parapet. It did not negate an undesirable state. Put differently: if the Torah had written only the positive commandment of parapet without a prohibition, I might have thought that not building a parapet is not a transgression but only an absence of merit.

Therefore the Torah adds a prohibition in order to strengthen the positive commandment. The meaning of the prohibition is that the state in which the roof lacks a parapet stands in direct contradiction to the Torah’s will. I can no longer think that failure to build is merely an absence of merit. It is now clear that this is a full transgression, because there is a direct, and not merely passive, collision with the Torah’s will.

So the prohibition strengthens the positive commandment by adding a stick to the carrot. If the positive commandment says: you ought to reach state A, and then you will be one who serves out of love and is righteous, the prohibition says: if you do not reach state A, you will be in state not-A, and that is a state the Torah forbids. Now you are not merely “not righteous,” but actually wicked, and you deserve punishment for being in a negative state.

We can now also understand why there is punishment for violating a negative commandment but not for neglecting a positive one. Failure to fulfill a positive commandment is an omission, even if it is carried out through a physical act, and therefore there is no punishment for it. Violation of a prohibition, by contrast, is normatively active wrongdoing that stands in direct conflict with the Torah’s will, and therefore it is punishable. For the same reason, one must spend all one’s property to avoid violating a prohibition, whereas one spends only one-fifth of one’s property on a positive commandment.

And Yet: Active Performance and Passive Abstention

In chapter A above, we cited the words of Nahmanides and the author of Tanya. Nahmanides explained that a positive commandment belongs to the category of love, as opposed to a prohibition, which belongs to service out of fear. And the author of Tanya explained that a positive commandment increases light—that is, reaches a positive state—whereas a prohibition prevents filth—that is, prevents one’s being in a negative state. Their intention is apparently exactly what we are saying here.

We can now understand that neglect of a positive commandment is, in essence, a non-frontal collision with the Torah’s will. It is a failure to arrive at a desired state. By contrast, violation of a prohibition is being in an undesirable state, and therefore it is a frontal movement against the Torah’s will.

So, at the logical level, a positive commandment is indeed a command of active performance: you must be in the positive state A. A prohibition, by contrast, is a command of abstention: do not be in the negative state B. Yet being or not being in those states can sometimes be achieved by action and sometimes by inaction—inaction here in the logical, not pejorative, sense.

We have therefore redefined the terms “active performance” and “passive abstention.” They do not refer specifically to actions, physical or otherwise, but to reaching or not reaching states. When the Torah points to an undesirable state, it thereby instructs me not to arrive at that state. When it points to a desirable state, it instructs me to arrive at that state. The distinction is not located on the physical axis of acting and refraining, but on the normative axis of desirable and undesirable.

And Yet, the Logical Problem

At first glance, all our problems have now been solved. It would seem that we can also understand why Maimonides, Nahmanides, and most of the medieval authorities do not regard a positive commandment and a prohibition as mere duplication, and count them as two separate commandments even when their contents overlap: in a positive commandment the Torah points to a desirable state, while in a prohibition it points to an undesirable state. By contrast, when there are two prohibitions or two positive commandments with the same content, the duplication is complete, and they are therefore not counted as two separate commandments.

But if we now return to the logical formulation of the problem, at the beginning of the present chapter, the picture is not so simple. The positive commandment of rest on the Sabbath means: be in a state of rest. The prohibition forbidding labor, that is, non-rest, on the Sabbath means: do not be in a state of non-rest. But are these not merely different formulations of exactly the same thing? We have seen that double logical negation returns us to the same state. So the negation of the state of non-rest means an instruction to be in a state of rest, and vice versa. It is therefore still not clear what the difference is between a positive commandment and a prohibition. The logical problem would seem to remain intact.

Normative Negation: Halakhic Illustrations

The solution to this problem lies in a subtle distinction, and it too requires moving from the logical axis to the normative one: the inversion between a positive commandment and a prohibition is not logical negation but normative negation. The command “Be in state A!” is not identical to the command “Do not be in state non-A!” In this case, surprisingly, double negation does not bring us back to the same point. The reason is that the negation here is not logical but normative. From a normative standpoint, the two commands above are not equivalent.

Let us illustrate this at the level of normative consequences. If the Torah commands us to build a parapet, and we were prevented by circumstances from doing so, then in that case we did not fulfill the positive commandment. In the language of the Jerusalem Talmud, Gittin 7:6, and Kiddushin 3:2, “compulsion is not as though one acted.” True, we are not at fault, since we acted under compulsion, and of course we are not punished, not even in Heaven, but in practice the positive commandment was not fulfilled.

By contrast, if the Torah commanded us: do not arrive at a state in which your house is without a parapet, then if I was prevented by circumstances it can be said—and there are indeed views to this effect—that I did not transgress at all: “compulsion is as though one did not act.” So from a normative standpoint, the command “Build a parapet!” is not equivalent to the command “Do not be in a state without a parapet!”

Alternatively, what happens if I have a house that already has a parapet, like the case of an infant born already circumcised? With respect to the commandment to build a parapet, I certainly have not fulfilled it—perhaps no commandment applies to me in such a case, but I certainly have not performed one. With respect to the prohibition, however, I certainly have violated nothing.

Or put differently: is there any reason to pursue ownership of a house in order to become obligated to build a parapet? With respect to the positive commandment, perhaps yes. With respect to the prohibition, certainly not.

Another consequence is the remark of Pnei Yehoshua cited above. With respect to the positive commandment, there is value in making the parapet oneself. With respect to the prohibition, there is no such value; the essential thing is simply that I not possess a house without a parapet. Indeed, perhaps there is reason specifically not to own a house, so as to avoid stumbling over the prohibition of parapet.

Normative Negation: A Logical Analysis

And yet this distinction still requires explanation. After all, the negation operator acts in the same way on every proposition, regardless of its nature. So double negation ought to bring me back to the starting point even when the matter at hand is a command rather than an assertion of fact. To say that chocolate is not tasty is the opposite of saying that chocolate is tasty, even if we do not regard these as factual claims but as value judgments. The same is true of claims that a given creation is beautiful or not beautiful, or that a given act is worthy or unworthy. Logic operates on every kind of human expression, and it is not clear how the normative sphere could be an exception.

To understand this, let us examine the matter through a completely formal logical analysis. Take the normative instruction that tells us to make a parapet, which is not assessed in terms of truth and falsehood, and replace it with a factual proposition:

(A) “I want you to make a parapet.”

This proposition can be evaluated as true or false, and therefore an operation of negation can be defined with respect to it. What is the negation of this proposition? At first glance, several possibilities suggest themselves:

(B1) “I do not want you to make a parapet.”

(B2) “I want you not to make a parapet.”

(B3) “It is false that I want you to make a parapet.”

The negation of a proposition is the proposition that always receives the opposite truth-value from the original proposition. If proposition A is the negation of B, that means that if A is true then B is false, and if A is false then B is true. Such negation is generated by adding the prefix “It is false that…” before the proposition being negated.

Now let us ask: which of the three propositions above is the negation of proposition A? Clearly, only proposition B3. It is the only one generated by adding that prefix before the negated proposition. We can now see this by repeated application of the negation operator:

(C1) “It is false that I do not want you to make a parapet.”

(C2) “It is false that I want you not to make a parapet.”

(C3) “I want you to make a parapet.”

Obviously, only proposition C3 returns us to the original proposition. Logical negation cancels logical negation, but not the other two, which are normative negations. The other two come close, but not exactly; in intuitionistic logic, C1 and C2 are not equivalent to A.

So double negation indeed operates on normative propositions too, like any other proposition, but for that one must apply the logical negation operator.

Now let us ask the following question: if proposition A is the positive commandment, what proposition expresses the corresponding prohibition? The answer is fairly clear:

(D) “I do not want you not to make a parapet.”

This is, in fact, the formulation parallel to the biblical command “Do not place blood in your house.” But this instruction is not equivalent to any of the propositions in group C above. The opposite of “I want” is “It is not true that I want,” not “I want not.” It is therefore clear that this formulation is not logically equivalent to formulation A, which expresses the positive commandment.

To summarize: logical negation relates to the truth-value of a proposition and reverses it. As noted, it is generated by adding the prefix “It is not true that…” before the proposition being negated. For example, it turns “A wants X” into “It is not true that A wants X.”

Normative negation, by contrast, relates to the will itself. It reverses the content of the will—the norm—and not the truth-value of the proposition. It replaces “A wants X” with “A wants not-X” or with “A does not want X.” That is why we call it “normative negation” as opposed to “logical negation.” We see here that there are several possible forms of normative negation, and each expresses a different normative operator, but this is not the place to elaborate.

Footnotes