Sforno on Deuteronomy 31:9/ספורנו על דברים ל״א:ט׳

1את התורה הזאת, a reference to the final commandment in the Torah, Hakhel, for the king to read the Torah once in seven years before the entire Jewish people, minors and babies in arms included.

2ויתנה אל הכהנים בני לוי, from whose hands the King who would read it in public would receive it. The Talmud Sotah 41 describes that the Torah scroll passed from the deputy High Priest’s hands to those of the High Priest himself, who in turn handed it to the King.

3הנושאים את ארון, one of the three occasions when the priests rather than the ordinary Levites carried the Ark; at the time when the miracle of the waters being split would occur once more, the priests carrying the Ark were the catalyst.

4ואל כל זקני ישראל, from whom the priests had received the Torah scroll on that occasion. On the folio in Sotah 41 mentioned earlier, the details of this whole procedure are described.