Deuteronomy 20:15-19

¹⁵So you are to do to all the towns far away, which are not the towns of these nations.

¹⁶But in the towns of these peoples whose land the Lord your God is giving you for your heritage, let no living thing be kept from death:

¹⁷Give them up to the curse; the Hittite, the Amorite, the Canaanite, the Perizzite, the Hivite, and the Jebusite, as the Lord your God has given you orders:

¹⁸So that you may not take them as your example and do all the disgusting things which they do in the worship of their gods, so sinning against the Lord your God.

¹⁹If in war a town is shut in by your armies for a long time, do not let its trees be cut down and made waste; for their fruit will be your food; are the trees of the countryside men for you to take up arms against them?