"Ashrei (Tehillah LeDavid) and Kedusha DeSidra—there is room to think they may be obligatory."
Why? For what reason??

With God's help, 6 Tevet 5783

To Please, greetings,

As for the aspect of "obligation" in "Tehillah LeDavid" and "Kedusha DeSidra," I do not know. That is a matter for the halakhic decisors. But it is clear that the Sages saw these things as having great importance. "Tehillah LeDavid" paves a person's way to being "a person destined for the World to Come," while "Kedusha DeSidra" is one of the things upon which the world stands.

The Sages saw great value in awakening a person's aspiration to resemble the angels and to sanctify God's name in the world just as the angels sanctify it in the highest heavens. It is no accident that the song of the angels in Isaiah's vision ("Holy, holy," etc.) and in Ezekiel's vision ("Blessed is the glory of the Lord from His place") was established to be said three times a day—in the blessing of Yotzer and in the blessing of the sanctification of the Name, at Shacharit and Minchah.

But the Sages did not make do with reciting the song of the angels; they also instituted the study of its Aramaic translation, so that every Jew would understand and know how one brings about the sanctification of God's name in the world.

The translation adds deep dimensions to the verses. Thus we learn that "and one called to another" does not mean "to come down on one another," but rather to bow one's head toward the other, to receive permission from one another. In other words, the sanctification of God's name in the world comes specifically through an approach of "crowning your fellow pleasantly and gently."

And the triple holiness is expounded as teaching that holiness must not exist only "in the highest heavens," but also in "the earth where His mighty acts are done." Here, in practical life full of burdens and trials, that is where a person must be among "the mighty ones who do His word," those who influence the world rather than being dragged along by its pressures and temptations.

The first holiness expresses the divine transcendence, which is far above even the world of the angels. The second holiness expresses the aspiration to make God's holiness present in this world. And the third holiness expresses the aspiration that holiness endure "forever and for all eternity"—and it is specifically the human being who can bring eternal holiness by passing the mission on to the coming generations, as it says: "The word of the Lord that is in your mouth shall not depart from your mouth, nor from the mouth of your children, nor from the mouth of your children's children." That is the Jewish version of the Pisa test 🙂

How is this done? Ezekiel teaches us this, as he hears the song of the angels at the moment when the Divine Presence is departing from this world at the time of the destruction. And precisely at that terrible moment, Ezekiel continues to hear behind him the guidance: "Blessed is the glory of the Lord from the place of His Presence." Even in its destruction, the place of the Temple radiates God's glory into the world. From this a person should internalize that even when he leaves the minor sanctuary for the storm of ordinary life, the song of the angels should still echo in his ears, so that he may fulfill: "In all your ways know Him."

Given the world's incomplete state, the cry bursts forth from the believer's mouth: "The Lord shall reign forever and ever." Here the translation balances us. The Lord will not only "reign" in the future. Even in "the concealment within the concealment," "the Lord's kingship stands"—present tense. He runs His world "behind the scenes," and has not, Heaven forbid, "abandoned the earth."

The early pietists would wait an hour before prayer in order to contemplate God's greatness, and an hour afterward in order to bring those great aspirations down into life. We, as ordinary Jews, make do with a few minutes of Pesukei DeZimra expressing the aspiration that "every soul praise the Lord," and a few minutes of "Kedusha DeSidra," in which we receive a "daily lesson" in how to carry the aspirations of holiness from above to below and from the here-and-now to future generations.

With blessing,
Yaron Fisch"l Ordner

It really is hard to know what here is obligatory, because in the laws of prayer there is a blurring (perhaps intentional) between recommendations and obligations. I can't give a clear answer, and that is why my wording was also vague.