Moses
Deuteronomy 32:43ESV·traditional attribution

“Rejoice with him, O heavens; bow down to him, all gods, for he avenges the blood of his children and takes vengeance on his adversaries. He repays those who hate him and cleanses his people’s land.”

John Calvin Reformed @genevareformer

43. Rejoice, O ye nations, with his people. The appositive reading, which some prefer, “Praise him, O nations, His people,” supplying the word “God,” is constrained. For there is no incongruity in the notion that the Gentiles should celebrate the benefits which God has conferred upon His people; at any rate, it is more simple to take it thus, that so conspicuous was the favor...

Matthew Henry Presbyterian @wholebiblehenry

This conclusion of the song speaks three things: I. Glory to God, Deu 32:39. "See now upon the whole matter, that I, even I, am he. Learn this from the destruction of idolaters, and the inability of their idols to help them." The great God here demands the glory, 1. Of a self-existence: I, even I, am he.

Commenting on Deuteronomy 32:39-43

John Gill Reformed Baptist @doctorgill

And Moses came,.... To the people, as the Greek version, the heads of the people being gathered together according to his order, Deu 31:28; The Targum of Jonathan says, he came from the tabernacle, the house of instruction: and spake all the words of this song in the ears of the people; which is observed both before and after the reading of it, to show...