Exodus 34:10-16

And he said, "Behold, I make a covenant. Before all your people I will do marvels, such as have not been wrought in all the earth or in any nation; and all the people among whom you are shall see the work of the Lord; for it is a terrible thing that I will do with you.

"Observe what I command you this day. Behold, I will drive out before you the Amorites, the Canaanites, the Hittites, the Perizzites, the Hivites, and the Jebusites. Take heed to yourself, lest you make a covenant with the inhabitants of the land whither you go, lest it become a snare in the midst of you. You shall tear down their altars, and break their pillars, and cut down their Asherim (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 when they play the harlot after their gods and make your sons play the harlot after their gods."