Deuteronomy 20:10-20

10When thou comest nigh unto a city to fight against it, then proclaim peace unto it. 11And it shall be, if it make thee answer of peace, and open unto thee, then it shall be, that all the people that is found therein shall be tributaries unto thee, and they shall serve thee. 12And if it will make no peace with thee, but will make war against thee, then thou shalt besiege it: 13And when Yhwh thy God hath delivered it into thine hands, thou shalt smite every male thereof with the edge of the sword: 14But the women, and the little ones, and the cattle, and all that is in the city, even all the spoil thereof, shalt thou take unto thyself; and thou shalt eat the spoil of thine enemies, which Yhwh thy God hath given thee.1 15Thus shalt thou do unto all the cities which are very far off from thee, which are not of the cities of these nations. 16But of the cities of these people, which Yhwh thy God doth give thee for an inheritance, thou shalt save alive nothing that breatheth: 17But thou shalt utterly destroy them; namely, the Hittites, and the Amorites, the Canaanites, and the Perizzites, the Hivites, and the Jebusites; as Yhwh thy God hath commanded thee: 18That they teach you not to do after all their abominations, which they have done unto their gods; so should ye sin against Yhwh your God.

19When thou shalt besiege a city a long time, in making war against it to take it, thou shalt not destroy the trees thereof by forcing an axe against them: for thou mayest eat of them, and thou shalt not cut them down (for the tree of the field is man’s life) to employ them in the siege:23 20Only the trees which thou knowest that they be not trees for meat, thou shalt destroy and cut them down; and thou shalt build bulwarks against the city that maketh war with thee, until it be subdued.4