Moses
Deuteronomy 3:2BSB·traditional attribution

But the LORD said to me, “Do not fear him, for I have delivered him into your hand, along with all his people and his land. Do to him as you did to Sihon king of the Amorites, who lived in Heshbon.”

Matthew Henry Presbyterian @wholebiblehenry

We have here another brave country delivered into the hand of Israel, that of Bashan; the conquest of Sihon is often mentioned together with that of Og, to the praise of God, the rather because in these Israel's triumphs began, Psa 135:11; Psa 136:19, Psa 136:20. See, I. How they got the mastery of Og, a very formidable prince, 1.

Commenting on Deuteronomy 3:1-11

John Gill Reformed Baptist @doctorgill

And the Lord said unto me,.... When Og was marching with all his forces against Israel: fear him not, &c; See Gill on Num 21:34.

Jamieson-Fausset-Brown Reformed @jfbcommentary

The Lord said unto me, Fear him not: for I will deliver him, and all his people, and his land, into thy hand--Og's gigantic appearance and the formidable array of forces he will bring to the field, need not discourage you; for, belonging to a doomed race, he is destined to share the fate of Sihon [Num 21:25].