Moses
Deuteronomy 32:39BSB·traditional attribution

See now that I am He; there is no God besides Me. I bring death and I give life; I wound and I heal, and there is no one who can deliver from My hand.

John Calvin Reformed @genevareformer

39 See now that 1, even I, am he. Those who attribute the preceding verses to the unbelievers, now introduce God speaking, as it were, abruptly, and asserting His glory, in rebuke of their blasphemies. But it is rather a confirmation of that holy boasting which He has just dictated to the believers, when God not only bids His people lift up their voices against...

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

For I lift up my hand to heaven,.... Which is a gesture used in swearing, Gen 14:22, and is ascribed to a divine Person, Eze 20:5; and particularly to Christ the angel, that is so wonderfully described, Rev 10:1; though sometimes it is used, as Aben Ezra observes, to excite the attention of hearers, but here it signifies swearing; and so the Targums of Jonathan...