“For he [the civil magistrate] is the servant of God, an avenger who carries out God’s wrath on the wrongdoer.” Rom. 13:4b
“Love does no wrong to a neighbor; therefore love is the fulfilling of the law.” Rom. 13:10
Many today criticize theonomy—the idea that God’s law should be the standard of justice in a society—out of a severe misconception. That misconception says that God’s law, as contained in the Old and New Testaments together, is barbaric and uncivilized. They say, furthermore, that such a situation would be the worst form of religious tyranny. These are strong claims, for sure. But do they accurately represent the theonomic vision? I say no, they do not.
The End of Law
Jesus was emphatic. The greatest commandment in the law is to love God “with all your heart and with all your soul and with all your mind.” And the second commandment is like this one, “You shall love your neighbor as yourself” (see Matt. 22:37-39). What law of God is Jesus talking about? A different law than what had been given already? No, Jesus is referring to the law contained in the Old Testament Scriptures. He goes on to say that on the commands to love God and neighbor “depend all the Law and the Prophets” (Matt. 22:40)—a clear reference to Old Testament law.
My point in saying all this is simple: theonomy is based upon love. Love for God causes us to reverence and honor His holy law. Love for my neighbor stirs up my desire to see justice done for the oppressed. But what is justice apart from the law of God? God is just, and His law defines justice for human relationships—even the civil magistrate.
Law of Liberty
Christianity is about freedom—freedom in Christ from sin and death. Freedom to worship God for eternity, to the praise of His glorious grace (Eph. 1:6). Freedom to live at peace with men because God in Christ has restored His elect to Himself, and He alone can restore the lives and relationships that are broken around us. James says that, “the one who looks into the perfect law, the law of liberty, and perseveres, being no hearer who forgets but a doer who acts, he will be blessed in his doing” (v. 1:25). In God’s law there is liberty—liberty founded upon love. Any other system will ultimately promote hatred and oppression.
John Calvin was correct when, writing to the King of France, he said the following:
“It will then be for you, most serene King, not to close your ears or your mind to such just defense, especially when a very great question is at stake: how God’s glory may be kept safe on earth, how God’s truth may retain its place of honor, how Christ’s Kingdom may be kept in good repair among us. Worthy indeed is this matter of your hearing, worthy of your cognizance, worthy of your royal throne! Indeed, this consideration makes a true king: to recognize himself a minister of God in governing his kingdom. Now, that king who in ruling over his realm does not serve God’s glory exercises not kingly rule but brigandage.” 
- John Calvin, Institutes of the Christian Religion, ed. John T. McNeill, trans. by Ford Lewis Battles, (Philadelphia, PA: 1960), 11-12.↵