Cur Deus Homo

by R.C. Sproul

In the eleventh century, one of the church’s most brilliant thinkers, Anselm, archbishop of Canterbury, wrote three important works that have influenced the church ever since. In the field of Christian philosophy, he gave us his Monologium and his Proslogium; in the field of systematic theology, he penned the great Christian classic Cur Deus Homo, which being translated means “Why the God-Man?”

In this work, Anselm set forth the philosophical and theological foundations for an important aspect of the church’s understanding of the atonement of Christ, specifically the satisfaction view of the atonement. In it, Anselm argued that it was necessary for the atonement to take place in order to satisfy the justice of God. That viewpoint became the centerpiece of classical Christian orthodoxy in the Middle Ages, in terms of the church’s understanding of the work of Christ in His atonement. Since then, however, the satisfaction view of the atonement has not been without its critics.

In the Middle Ages, questions were raised about the propriety of thinking that the atonement of Jesus was made necessary by some abstract law of the universe that required God’s justice to be satisfied. This gave rise to the so-called Ex Lex debate. In the Ex Lex debate, the question was raised as to whether God’s will functioned apart from any law or outside of any law (ex lex), or whether the will of God was itself subjected to some norm of righteousness or cosmic law that God was required to follow and, therefore, His will was exercised under law (sub lego). The question was: Is God apart from law or is He under law?

The church’s response to this dilemma was to say basically “a pox on both houses,” and to declare that God is neither apart from law nor under law in these respective senses. Rather, the church responded by affirming that God is both apart from law and under law, in so far as He is free from any restraints imposed upon Him by some law that exists outside of Himself. In that sense, He is apart from law and not under law. Yet at the same time, God is not arbitrary or capricious and works according to the law of His own nature. The church declared that God is a law unto Himself. This reflects not a spirit of lawlessness within God, but that the norm for God’s behavior and God’s will is based on what the seventeenth-century orthodox theologians called “the natural law of God.”

The natural law of God, as a theological expression, can be easily misunderstood or confused with the broader concept that we encounter in political theory and in theology of the so-called “law of nature” (lex naturalis). In that sense of the phrase, the law of nature refers to those things that God reveals in the world of nature about certain principles of ethics. In distinction from this common use of the term natural law, what the seventeenth-century Westminster divines had in view when they spoke of the natural law of God was this: that God operates according to the law of His own nature. That is to say, God never acts in such a way that would contradict His own holiness, His own righteousness, His own justice, His own omnipotence, and so on. God never compromises the perfection of His own being or character in what He does.

When the church confesses the necessity of the satisfaction of God’s righteousness, this necessity is not something that is imposed upon God from the outside, but it is a necessity imposed upon God by His own character and nature. It is necessary for God to be God, never to compromise His own holiness, righteousness, or justice. It is in this sense that an atonement that satisfied His righteousness is deemed necessary.

In more recent times, modern thinkers have objected to the satisfaction view of the atonement on the grounds that it casts a shadow over the free grace and love of God. If God is a God of love, why can He not just forgive people gratuitously from the pure motivation of His own love and grace, without being concerned about satisfying some kind of justice, whether it’s a law of His own nature or a law imposed from without? Again, this view of the atonement fails to understand that God will never negotiate His own righteousness, even out of His desire to save sinners.

In the atonement, we see that God both manifests His gracious love towards us and yet at the same time, manifests a commitment to His own righteousness and justice. Justice is served by the work of Christ who satisfies the demands of God’s righteousness, thereby maintaining God’s commitment to righteousness and justice. God satisfied the demands of His righteousness by giving to us a Substitute who stands in our place, offering that satisfaction for us. This displays marvelously the graciousness of God in the midst of that satisfaction. God’s grace is illustrated by the satisfaction of His justice in that it is done for us by the One whom He has appointed. It is God’s nature as the Judge of all the world to do what is right. And the Judge who does what is right never, ever violates the canons of His own righteousness.

The Bible explains the cross in terms of both propitiation and expiation, the twin accomplishments of Christ in our behalf. Propitiation refers specifically to Christ’s work of satisfaction of God’s righteousness. He pays the penalty for us that is due our sins. We are debtors who cannot possibly pay the moral debt that we have incurred by our offense against the righteousness of God, and God’s wrath is satisfied and propitiated by the perfect sacrifice that Christ makes on our behalf. But that’s only one aspect of the work. The second is expiation. In expiation, our sins are removed from us, remitted by having our sins transferred or imputed to Christ, who vicariously suffers in our stead. God is satisfied, and our sin is removed for us in the perfect atonement of Jesus. This fulfills the dual sense in which sin was atoned for on the old-covenant Day of Atonement, both by the sacrifice of one animal and the symbolic transfer of the sins of the people to the back of the scapegoat, who was then sent into the wilderness, removing the sins from the people.