Now before I became a Christian I was under the impression that the first thing Christians had to believe was on 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 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.P. 55
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.
Only a bad person needs to repent: only a good person can repent perfectly. The worse you are the more you need it and the less you can do it. The only person who could do it perfectly would be a perfect person--and he would not need it. ... But supposing God became man--suppose our human nature which can suffer and die was amalgamated with God's nature in one person--then that person could help us. He could surrender His will, and suffer and die, because He was man; and He could do it perfectly because He was God. You and I can go through this process only if God does it in us; but God can do it only if He becomes a man. Our attempts at this dying will succeed only if we men share in God's dying, just as our thinking can succeed only because it is a drop out of the ocean of His intelligence: but we cannot share God's dying unless God dies; and He cannot die except by being a man. That is the sense in which He pays our debt, and suffers for us what He Himself need not suffer at all.