Deuteronomy 20:18 in the King James Version
That they teach you not to do after all their abominations, which they have done unto their gods; so should ye sin against the LORD your God.
Context
17 but you shall utterly destroy them: the Hittite, the Amorite, the Canaanite, the Perizzite, the Hivite, and the Jebusite, as the LORD your God has commanded you;
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?