Deuteronomy 20:15-19

¹⁵Thus shalt thou do unto all the cities which are very far off from thee, which are not of the cities of these nations.

¹⁶Howbeit of the cities of these peoples, that the LORD thy God giveth thee for an inheritance, thou shalt save alive nothing that breatheth,

¹⁷but thou shalt utterly destroy them: the Hittite, and the Amorite, the Canaanite, and the Perizzite, the Hivite, and the Jebusite; as the LORD thy God hath commanded thee;

¹⁸that they teach you not to do after all their abominations, which they have done unto their gods, and so ye sin against the LORD 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 wielding an axe against them; for thou mayest eat of them, but thou shalt not cut them down; for is the tree of the field man, that it should be besieged of thee?