Deuteronômio 31:28 Comentário: Rashi, Chizkuni, Sforno & Rabbeinu Bahya

הקהילו אלי ASSEMBLE UNTO ME [ALL THE ELDERS OF YOUR TRIBE] — They did not, however, blow the trumpets that day to call the congregation together (as is prescribed in Numbers 10:3), because it states (Numbers 10:2) “Make for thee [two trumpets of silver]” (which Rashi explains to mean that no one should use them except himself), and he had not empowered Joshua to use them. Indeed they were hidden away even during his (Moses) lifetime — on the day of his death, thus fulfilling the words of the text, (Ecclesiastes 8:8) “There is no authority on the day of death” (cf. Midrash Tanchuma, Vayechi 2 on ויחי and ‎Midrash Tanchuma, Beha'alotcha 10 on בהעלתך).‎

ואעידה בם את השמים ואת הארץ, “and I will appoint as witnesses against them Heaven and Earth.” Here Moses actually appointed Heaven and Earth as witnesses, while earlier (in verse 30.19) he merely told the Jewish people that these would be witnesses against them.

ואדברה באזניהם את הדברים האלה, the words of poetry contained in the portion Haazinu.

ואעידה בם את השמים ואת הארץ I WILL CALL THE HEAVEN AND THE EARTH AS WITNESSES AGAINST THEM — But if you ask, “Behold he has already above (Deuteronomy 30:19) called heaven and earth as witnesses: “I call [the heaven and the earth] as witnesses this day against you etc.”?! Then I reply: There he said this to the Israelites (he told them that He would do this), but now he intends to say (Deuteronomy 32:1) “Give ear, O ye heavens, [and I will speak; and hear earth] etc.”, thus calling them as witnesses.