Deuteronomy 20:19 in the King James Version
When 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:
Context
18 that they not teach you to follow all their abominations, which they have done for their gods; so would you sin against the LORD your God.
19 When you shall besiege a city a long time, in making war against it to take it, you shall not destroy its trees by wielding an ax against them; for you may eat of them. You shall not cut them down, for is the tree of the field man, that it should be besieged by you?
20 Only the trees that you know are not trees for food, you shall destroy and cut them down. You shall build bulwarks against the city that makes war with you, until it falls.