Deuteronomy 20:14-18

14Only the women and the children and 1the animals and all that is in the city, all its spoil, you shall take as booty for yourself; and you shall 2use the spoil of your enemies which the Lord your God has given you. 15Thus you shall do to all the cities that are very far from you, which are not of the cities of these nations 3nearby. 164Only in the cities of these peoples that the Lord your God is giving you as an inheritance, you shall not leave alive anything that breathes. 17But you shall 5utterly destroy them, the Hittite and the Amorite, the Canaanite and the Perizzite, the Hivite and the Jebusite, as the Lord your God has commanded you, 18so that they may not teach you to do 6according to all their detestable things which they have done for their gods, so that you would 7sin against the Lord your God.