11 Observe thou that which I command thee this day: behold, I drive out before thee the Amorite, and the Canaanite, and the Hittite, and the Perizzite, and the Hivite, and the Jebusite.

12 Take heed to thyself, lest thou make a covenant with the inhabitants of the land whither thou goest, lest it be for a snare in the midst of thee:

13 But ye shall destroy their altars, break their images, and cut down their groves:

14 For thou shalt worship no other god: for the Lord, whose name is Jealous, is a jealous God:

As part of the Lord re-extending His covenant to bring Israel into the Promised Land, He now describes all of the enemies that currently dwell in that land, whom He will drive out to make space for His chosen people. God then warns the Israelites against making any sort of liaison with those people. The Canaanites had been marked for destruction because of their perversions, and anyone that became confederate with them would be linking themselves to their doom. Instead, the Israelites were commanded to remain firmly apart, and to tear down any of the false gods that they came across.

While the Lord did not specifically bring to mind Israel’s recent offense, these instructions must have been a timely reminder for how fundamentally they had betrayed their covenant to Him with the worship of the golden calf, taking a step towards the same idolatry of the Canaanites. In that one act they had broken God’s first two commandments. Indeed, the supplanting of God with any other ideal is the first of all wickedness. If the first and great commandment is to love the Lord with all of your heart, then the first and great sin must be to replace Him with something else.

Thus, God says in verse 14 that He is a jealous God. He is necessarily an exclusive God, one that must permeate all of our lives and not be mixed with alternative beliefs. Indeed, He cannot be mixed with alternative beliefs, for once one tries to mix, they have already cast aside God.