Deuteronomy 20:14-16

Amplified Bible

¹⁴ Only the women and the children and the animals and everything that is in the city, all its spoil, you shall take as plunder for yourself; and you shall use the spoil of your enemies which the Lord your God has given you. ¹⁵ That is what you shall do to all the cities that are very far away from you, which are not among the cities of these nations nearby [which you are to dispossess]. ¹⁶ Only 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.