Exodus 34:14-16

34:14 For you must not worship any other god, for the Lord, whose name is Jealous, is a jealous God. 34:15 Be careful not to make a covenant with the inhabitants of the land, for when they prostitute themselves to their gods and sacrifice to their gods, and someone invites you, you will eat from his sacrifice; 34:16 and you then take his daughters for your sons, and when his daughters prostitute themselves to their gods, they will make your sons prostitute themselves to their gods as well.