Parashas Vayeilech · Passuk 31:24
When Moses had put down in writing the words of this Teaching to the very end,
Torah Temimah points to Gittin 60a (גיטין ס' א').
English: who reads from the Torah? An answer was not readily available to him. He came and asked Rabbi Yitzḥak Nappaḥa, who said to him: After them read the Torah scholars who are appointed as leaders [parnasim] of the community. And after them read Torah scholars who are fit to be appointed as leaders of the community, even if in practice they received no such appointment. The Sages said that a Torah scholar who knows how to answer any question asked of him is fit to be appointed as leader of the community. And after them read the sons of Torah scholars whose fathers were appointed as leaders of the community. And after them read the heads of synagogues, and after them any person. The people of the Galilee sent a question to Rabbi Ḥelbo: What is the halakha with regard to reading from ḥumashim, i.e., scrolls containing only one of the five books of the Torah, in the synagogue in public? Is this permitted, or is it necessary to read from a complete Torah scroll? An answer was not readily available to him. He came and asked Rabbi Yitzḥak Nappaḥa, but an answer was not readily available to him either. Rabbi Yitzḥak Nappaḥa came and asked this question in the study hall, and they resolved the difficulty from that which Rabbi Shmuel bar Naḥmani says that Rabbi Yoḥanan says: With regard to a Torah scroll that is missing even one sheet of parchment, one may not read from it in public. This indicates that an incomplete Torah scroll may not be used for a public Torah reading. The Gemara rejects this argument: But that is not so, i.e., this cannot serve as a proof to the matter at hand. There, it is lacking part of the matter it is addressing, as a sheet of parchment is missing, whereas here, it is not lacking part of the matter it is addressing, as it contains a complete book. Rabba and Rav Yosef both say: One does not read from ḥumashim in the synagogue out of respect for the community. And Rabba and Rav Yosef both say: It is prohibited to publicly read the haftara, the portion from the Prophets that is read after the weekly Torah portion, on Shabbat, from a scroll containing only the haftarot. What is the reason for this? It is because this type of scroll may not be written, as the words of the Prophets must also be written as complete books. Mar bar Rav Ashi said: To handle such a scroll on Shabbat is also prohibited. What is the reason for this? It is because it is not fit to be read. Consequently, it is treated as set-aside [muktze] on Shabbat. The Gemara rejects this argument: But that is not so; rather, it is permitted to handle such a scroll and it is permitted to read from it. And a proof for this is that Rabbi Yoḥanan and Rabbi Shimon ben Lakish used to read from a scroll of aggada containing the words of the Sages on Shabbat.
Derash on the verse (Bavli sugya) — not a formal named middah of the 13
The Gemara uses this passuk inside a sugya (question, proof, or illustration). That is classical derash, but not labeled here as one of R' Yishmael’s 13 unless the move is explicit.
Completing the writing of the Torah ‘to the end’ marks a finished Torah scroll as a closed, authoritative text entrusted to the Levi’im.