Deuteronomy 3:3 (ESV)

3 So the LORD our God gave into our hand Og also, the king of Bashan, and all his people, and we struck him down until he had no survivor left.

Moses describes the success of Israel in battle as the Lord's doing: he gave Og into Israel's hand. The action of man is stated only in the second place, that Israel smote the enemy until not a single survivor was left.