Deuteronomy 20:15-19

¹⁵This is the way you are to deal with all the towns that are a long way from you and don't belong to neighboring nations.

¹⁶However, when it comes to the towns of those nations whose land the Lord your God is giving you to occupy, don't leave anything alive that breathes.

¹⁷Set them apart for complete destruction—the Hittites, Amorites, Canaanites, Perizzites, Hivites, and Jebusites—as the Lord your God has ordered you to do.

¹⁸This is to prevent them teaching you all the offensive things they do in worshiping their gods, and in so doing make you sin against the Lord your God.

¹⁹Now when you lay siege to a town and it goes on for a long time as you fight to capture it, don't destroy the fruit trees there. You can eat their fruit. Don't cut them down. Are the trees in the orchard human beings that you should also attack?