Deuteronômio 31:22 Midrash: Sifrei Devarim & Mekhilta DeRabbi Yishmael

(Devarim 1:1) "These are the words which Moses spoke, etc.": Now did Moses prophesy only these? Did he not write the entire Torah, viz. (Ibid. 31:9) "And Moses wrote this Torah"? What, then, is the intent of "These are the words"? We are hereby taught that they were words of rebuke, viz. (Ibid. 32:15) "And Yeshurun grew fat and it kicked, etc."

Variantly: "Moses and the children of Israel": We are hereby apprised that Moses chanted the song opposite all of Israel (i.e., that his voice was over and against those of all of Israel.) "this song": There are ten "songs." The first, that sung in Egypt, viz. (Isaiah 30:29) "The song (of Sancherev's destruction [on Pesach night]) will be to you as that of the night on which you sanctified the festival (Pesach [in Egypt]), etc." The second, that of the sea — "Then Moses sang." The third, that of the well (Numbers 21:17) "Then Israel sang." The fourth, that of Moses, viz. (Devarim 31:22) "And Moses wrote this song (32:1-43). The fifth, that of Joshua, viz. (Joshua 10:12) "Then Joshua spoke to the L–rd on the day the L–rd delivered, etc." The sixth, that of Devorah and Barak, viz. (Judges 5:1) "And Devorah and Barak the son of Avinoam sang, etc." The seventh, that of David, viz. (II Samuel 22:1) "And David spoke to the L–rd the words of this song, etc."