Deuteronomy 7:2

7:2 and he delivers them over to you and you attack them, you must utterly annihilate them. Make no treaty with them and show them no mercy!

Deuteronomy 7:22

7:22 He, the God who leads you, will expel the nations little by little. You will not be allowed to destroy them all at once lest the wild animals overrun you.