Deuteronomy 31:3-5

The LORD your God himself will go over before you. He will destroy these nations before you, so that you shall dispossess them, and Joshua will go over at your head, as the LORD has spoken. And the LORD will do to them as he did to Sihon and Og, the kings of the Amorites, and to their land, when he destroyed them. And the LORD will give them over to you, and you shall do to them according to the whole commandment that I have commanded you.