The civil magistrate cannot function without some ethical guidance, without some standard of good and evil. If that standard is not to be the revealed law of God… then what will it be? In some form or expression, it will have to be the law of man (or men)—the standard of self-law or autonomy. And when autonomous laws come to govern a commonwealth, the sword is certainly wielded in vain, for it represents simply the brute force of some men’s will against the will of other men.
-Greg L. Bahnsen