Exodus 34:14-16

(for you shall worship no other god, for the LORD, whose name is Jealous, is a jealous God), lest you make a covenant with the inhabitants of the land, and they play the harlot with their gods and make sacrifice to their gods, and one of them invites you and you eat of his sacrifice, and you take of his daughters for your sons, and his daughters play the harlot with their gods and make your sons play the harlot with their gods.