Exodus 34:12-16

34:12 Be careful not to make a covenant with the inhabitants of the land where you are going, lest it become a snare among you. 34:13 Rather you must destroy their altars, smash their images, and cut down their Asherah poles. 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.

Deuteronomy 7:2-3

7:2 and he delivers them over to you and you attack them, you must utterly annihilate them. Make no treaty with them and show them no mercy! 7:3 You must not intermarry with them. Do not give your daughters to their sons or take their daughters for your sons,