C.S. Lewis on Substitutionary Atonement

God providing a sacrifice in place of Isaac

How does Messiah's death reconcile us to God? 

It's a central argument of Christian faith: people should follow Jesus and turn from their sins because his death reconciles us to God. 

But how does it reconcile us to God?

A common answer to this question is substitutionary atonement. In this theory, God, being a just judge, must punish sin. A judge who doesn't punish criminals isn't just, after all. This theory says Jesus died in our place: people deserve death because of their sins, and God, being a righteous judge, has to punish sin. But Jesus voluntarily took the punishment instead. God's wrath and justice are satisfied, and humans are reconciled back to God.

Making my way through C.S. Lewis' Mere Christianity, he addresses this in a way that surprised me.

C.S. Lewis says the important part isn't the way Jesus reconciles us to God, the important part is the reality that Jesus has reconciled us:

Now before I became a Christian I was under the impression that the first thing Christians had to believe was one particular theory as to what the point of this dying was. According to that theory God wanted to punish men for having deserted and joined the Great Rebel, but Christ volunteered to be punished instead, and so God let us off. Now I admit that even this theory does not seem to me quite so immoral and so silly as it used to; but that is not the point I want to make. What I came to see later on was that neither this theory nor any other is Christianity. The central Christian belief is that Christ's death has somehow put us right with God and given us a fresh start. Theories as to how it did this are another matter. A good many different theories have been held as to how it works; what all Christians are agreed on is that it does work.

You might ask, what good is Jesus' death if we don't understand how it reconciles us to God?

Lewis answers with an analogy. A man can eat his dinner without understanding exactly how food nourishes him. A man can accept what Christ has done without knowing how it works: indeed, he certainly would not know how it works until he has accepted it.

This is one of those, "Well, rationality and intellect must bow to God too" moments. I don't care for these moments. But I don't want to make my rationality into God, so it must bow too.

Lewis elaborates,

We are told that Christ was killed for us, that His death has washed out our sins, and that by dying He disabled death itself. That is the formula. That is Christianity. That is what has to be believed. Any theories we build up as to how Christ's death did all this are, in my view, quite secondary: mere plans or diagrams to be left alone if they do not help us, and, even if they do help us, not to be confused with the thing itself. 

He digs a bit deeper into the substitutionary atonement theory:

The one [theory] most people have heard is the one I mentioned before - the one about our being let off because Christ had volunteered to bear a punishment instead of us. Now on the face of it that is a very silly theory. If God was prepared to let us off, why on earth did He not do so? And what possible point could there be in punishing an innocent person instead? None at all that I can see, if you are thinking of punishment in the police-court sense. On the other hand, if you think of a debt, there is plenty of point in a person who has some assets paying it on behalf of someone who has not. OR if you take the "paying the penalty", not in the sense of being punished, but in the more general sense of "standing in the racket" or "footing the bill", then, of course, it is a matter of common experience that, when one person has got himself into a hole, the trouble of getting him out usually falls on a kind friend."

Ha, alright C.S.! I don't find his "why didn't God just forgive straight away" line of thinking convincing - it seems to me the answer is clear: because God must punish sin for Him to be just. 

But I do like Lewis' reasoning that is it like footing the bill. The "kind friend" aligns well with the idea often championed in Messianic Jewish circles: that the merit of Messiah is credited towards us in our standing before God. We are in debt to God by our rebellion, but if we are in Messiah, God views us through the merit and righteousness of Messiah.

My big takeway here is the reduced importance of substitutionary atonement theory. In my mind's eye, I had always understood that to be crucial to understanding the work of Messiah. But I find convincing Lewis' argument that what matters is that Christ brings us near to God by erasing our sins. Theories about why this is true are of secondary importance.