There is the book The Reasons for the Commandments in Jewish Literature by Yitzhak Heinemann, which gives a nice overview.

What are commandments?

Thanks.

Commandments are the Holy One’s instructions to us of do and do not do.

Sources, authority, classifications, general rationales, what halakhic ruling is… (similar, for example, to Maimonides’ introduction to the Mishneh Torah or Rav Sherira Gaon’s Epistle).

I have an article in the volume published for Rabbi Rabinovitch’s eightieth jubilee. It also appears here on the site.
Halakhic ruling is an entirely different matter.

Thank you. Maybe that’s what you call there reflective literature.
If there is also something more basic, and not only Maimonides.

In any case, thank you for that article.

I’m not familiar with any. In my article there are many references to articles and books.

I wasn’t able to understand the hierarchy between 1 – laws that are called “a law given to Moses at Sinai” and 2 – laws that are derived through the interpretive principles by which the Torah is expounded.
I understood that group 2 can include laws for which there is a strong tradition, and laws for which there is no strong tradition, but all of them are also derived by exposition from the text.
I didn’t understand what group 1 includes — laws that are called “a law given to Moses at Sinai” — do these also have support in the scriptural texts, or do they exist only by virtue of the strong tradition?
Is group 2 never called in any way “a law given to Moses at Sinai,” even when there is a strong tradition?

There is no hierarchy. There are differences. According to most approaches, both are Torah-level. According to Maimonides, both are words of the Sages.
There is a mix-up here between commandments and laws. Commandments are the 613 that are written in the Torah or derived from it by straightforward exposition. Everything else is law — whether Torah-level or rabbinic — but not commandments.
A law given to Moses at Sinai is by definition a law regarding which there is a tradition from Sinai. This isn’t a matter of stronger or weaker. Laws derived from the text are usually laws regarding which there is no tradition, unless the exposition is merely supportive. In any case, these are laws and not commandments.
Literally, “a law given to Moses at Sinai” is everything that was given to Moses at Sinai. But in accepted terminology it refers to laws that have no anchor in the text, only an oral tradition. And again, these are not commandments but laws.

Oh, sorry — basic as this is, it isn’t clear to me. From what you said I understood that Jewish law is: everything that determines, at the Torah level, how to fulfill one of the 613 commandments + everything that determines, at the rabbinic level, how to fulfill one of the 613 commandments + everything that was originally established by the rabbis and is entirely outside the 613, such as lighting Hanukkah candles? So really there is no such thing as commandments that are only from the Oral Torah, and also no such thing as commandments that are rabbinic?
I understood that this is not a hierarchy but types. But the definitions aren’t clear.
Thanks for the patience.

Jewish law is everything that the Holy One expects us to do. That includes commandments, which are written in the Torah, and in addition several other kinds of laws (which it is not customary to call commandments): laws derived from expositions, laws given to Moses at Sinai, rabbinic laws (enactments and decrees). What is written in the Written Torah and what was received as a law given to Moses at Sinai (orally) are laws that came through a tradition from Sinai. Everything else is law that was created over the generations. In Jewish law there is no status of weak or strong tradition. Of course, even the laws received at Sinai undergo interpretation according to the understanding of the Sages.
The division between the Oral Torah and the Written Torah is a vague division and has no halakhic significance. It is terminological, not halakhic. Interpretation or exposition of the Written Torah is Oral Torah, but that interpretation determines what the commandment in the Written Torah is. Rabbinic laws are generally not even classified as Oral Torah, but again, that is only a matter of terminology.
There is hierarchy in Jewish law, for example between Torah-level laws and rabbinic laws. There are also different degrees of stringency within Torah-level law. But there is no hierarchy between laws given to Moses at Sinai and laws derived through exposition. The two types have the same status.

Thank you very much. I understood some things, but really my first question remains open. And the article also says that “laws derived through exposition are not counted in the enumeration of the commandments, unless the Sages determined that these are Torah-level laws, in which case they should be counted.”
So that is a bit confusing. I just want to make sure I’m not mistaken now:
1. Laws derived through exposition sometimes have the status of Torah-level law and sometimes the status of rabbinic law. But a law given to Moses at Sinai is always considered Torah-level. That is, there could be a hierarchy between them in that respect.
2. Laws derived through exposition that the Sages determined are Torah-level do not automatically become “commandments”; rather, that depends on additional criteria that distinguish between a law and a commandment.
3. Terminologically — only a law given to Moses at Sinai is a law that is both part of the Oral Torah and also always of Torah-level status.

What you brought from the article is Maimonides’ view. He holds that anything that is not written explicitly in the Torah or derived by straightforward methods is not included in the enumeration of the commandments.
1. Laws derived through exposition, according to Maimonides, have the status of words of the Sages and not Torah-level law (that is what emerges from his wording in the second root, although many of his commentators disagree with this. In my opinion, they are mistaken). There are exceptional cases in which the Sages tell us that this is a supportive exposition and not a creative one (that is, the exposition merely supports a known law after the fact), and then it is Torah-level and is counted. But those are the exceptions.
A law given to Moses at Sinai is always words of the Sages according to Maimonides.
2. No. According to Maimonides, if the exposition is supportive, then these are commandments that are counted.
3. No. A law given to Moses at Sinai is a law transmitted in a tradition from Sinai and has no anchor in the text or in expositions of the texts.
And all this is only Maimonides’ view, and even regarding that there are disputes.
It is very hard to explain a complicated topic from the beginning in a thread like this.

All right, thanks for the attempt. If there is a book or series of articles that explains this from the beginning even for someone who isn’t familiar with the depths of the material, I’d be glad to hear.
For someone looking from the outside and trying to understand the classification of what is called Jewish law and the truth of how it developed, it is almost impossible and feels like one meaningless lump (“the Torah, and everything the rabbis added…” ). But even for someone on the inside who grew up on vague concepts and partial Torah learning, there is a mess in the head.
It feels like there is a lack of terms. The same term includes several different entities, and that complicates even more what is already complicated enough. Someone who is deeply familiar with the material presumably doesn’t need more terms and therefore doesn’t create them.
Maybe a thousand years after the Mishneh Torah and five hundred years after the Shulchan Arukh, this too could be organized in a clearer way.
Thank you very much in any case.