Deuteronomy 20:14-18

However, the women, the children, the animals, and everything that is in the city, all of its spoils, you shall take as plunder for yourself; and you shall use the spoils of your enemies which the Lord your God has given you.

This is what you shall do to all the cities that are very far from you, which are not of the cities of these nations nearby.

Only in the cities of these peoples that the Lord your God is giving you as an inheritance, you shall not leave anything that breathes alive.

Instead, you shall utterly destroy them, the Hittite and the Amorite, the Canaanite and the Perizzite, the Hivite and the Jebusite, just as the Lord your God has commanded you,

so that they will not teach you to do all the same detestable practices of theirs which they have done for their gods, by which you would sin against the Lord your God.