I expect most of us have experienced it: we’re driving down a road above the posted speed limit, and suddenly we notice a police car up ahead on the side of the road. We immediately slow down to the speed limit, only to discover as we pass the police car that it is empty. The mere presence of the law embodied in that unoccupied police car restrained our lawlessness—at least for a moment.
In the sixteenth century, the Protestant Reformers identified three “uses” of the law of God: the civil use (a leash that restrains our corruption), the pedagogical use (a mirror that reveals our sinfulness and points us to Jesus Christ as the only Savior of sinners), and the normative use (a straightedge that guides us in how to please God). The church sometimes thinks of the restraining function of the law as limited to the unregenerate, who need the threat of punishment or the fear of shame to hinder them from being as evil as they might be if left to their own fallen hearts. Yet it is vital to recognize that God’s law also inhibits indwelling sin in those who have been born again, and that this function of the law is one of the ways God enables His people to be the city on a hill He has saved us to be.