Deuteronomy 20:13-18

13When the Lord your God gives it into your hand, 1you shall strike all the 2men in it with the edge of the sword. 14Only the women and the children and 3the animals and all that is in the city, all its spoil, you shall take as booty for yourself; and you shall 4use 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 5nearby. 166Only 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 7utterly 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 8according to all their detestable things which they have done for their gods, so that you would 9sin against the Lord your God.