Deuteronomy 20:13-19 (New International Version)
New International Version (NIV)
13 When the Lord your God delivers it into your hand, put to the sword all the men in it. 14 As for the women, the children, the livestock and everything else in the city, you may take these as plunder for yourselves. And you may use the plunder the Lord your God gives you from your enemies. 15 This is how you are to treat all the cities that are at a distance from you and do not belong to the nations nearby.
16 However, in the cities of the nations the Lord your God is giving you as an inheritance, do not leave alive anything that breathes. 17 Completely destroy[a] them—the Hittites, Amorites, Canaanites, Perizzites, Hivites and Jebusites—as the Lord your God has commanded you. 18 Otherwise, they will teach you to follow all the detestable things they do in worshiping their gods, and you will sin against the Lord your God.
19 When you lay siege to a city for a long time, fighting against it to capture it, do not destroy its trees by putting an ax to them, because you can eat their fruit. Do not cut them down. Are the trees people, that you should besiege them?[b]