Deuteronomy 20:10-20

10“When you go near a city to fight against it, call out shalom to it.

11Now if it answers you shalom and opens up to you, then all the people found in it will serve you as forced laborers.

12If it does not make peace with you but makes war against you, then lay siege against that city.

13When Adonai your God hands it over to you, you are to strike all its males with the sword.

14Only the women, children, livestock and all that is in the city—all its spoil—may you take as plunder for yourself. So you may consume your enemies’ spoil, which Adonai your God has given you.

15Thus you will do to all the cities that are very distant from you, which are not among the towns of these nations nearby.

16However, only from the cities of these peoples, which Adonai your God is giving you as an inheritance, you must not let anything that breathes live.

17You must utterly destroy them—the Hittites , the Amorites , the Canaanites , the Perizzites , the Hivites and the Jebusites—just as Adonai your God has commanded you.

18You are to do this so they will not teach you to do all the abominations as they have done for their gods, and so you would sin against Adonai your God.

19“When you lay siege to a city for a long time, making war against it to capture it, you are not to destroy its trees by swinging an axe at them. For from them you may eat, so you shall not chop them down. For is the tree of the field human, that it should enter the siege before you?

20You may destroy and chop down only the trees that you know are not trees for food, so that you may build siege equipment against the city that is making war with you until its downfall.