Deuteronomy 12:2
Ye shall utterly destroy all the places, wherein the nations which ye shall possess served their gods, upon the high mountains, and upon the hills, and under every green tree: Ye shall utterly destroy all the places, wherein the nations which ye shall possess served their gods, upon the high mountains, and upon the hills, and under every green tree:
God guarded Israel against idolatry by commanding the utter destruction of all the places where the nations to be dispossessed had served their gods. The places marked for destruction were upon the high mountains and upon the hills and under every green tree, that is the high places, hills, and tree-shaded groves of pagan worship, and worship conducted there was idolatry. Under every green tree means in groves dedicated to idols, where handmade idols were set beneath evergreen trees and the groves were made attractive places for idolatrous worship, corrupting things provided for human benefit to a perverse use. Those attractive groves, with their shrines, temples, and altars, had to be destroyed because their appeal could deceive the people and displace God in their minds.