Now I come to two doctrines of Luther in which the Reformation is so far superior to everything which is going on today in popular Christianity that I want to emphasize this very much, namely his doctrine of sin and faith. For Luther sin is unbelief. “Unbelief is the real sin.””Nothing justifies except faith, and nothing makes sinful except unbelief.” “Unbelief is the sin altogether .” “The main justice is faith, and so the main evil is unbelief.” Therefore the word ‘sin’ includes what we are living and doing besides the faith in God.” Now this presupposes a concept of faith which has nothing whatsoever to do with the acceptance of doctrine so I come to this immediately. But first what does it do for the concept of sin? It means that the differences of quantity (heavy and light sins), of relativity (sins which can be forgiven, in this or that way) do not matter at all. What they mean is only sin if it is related to God. Everything which separates us from Him has equal weight; they are not more or less; they have qualitative character. This means that for Luther, life as a whole, nature and substance, are corrupted.
And here I want to say something immediately about this term “total corruption,” or depravity, which you will often hear. Please understand this in the right way. It does not mean that nothing is good in man – no Reformer or Neo-Reformation theology ever said that. But it means that there are not parts in man which are exempted from existential distortion; for instance, not his thinking, or some other part in him. And in this sense the concept of total depravity would be translated by a modern psychologist: man is distorted, or in conflict with himself, in the center of his personal life. This means that everything is included, and that is what Luther meant. And if somebody speaks of “total,” then please always ask whether he means it in the absurd way – which would make it impossible to say that he is totally depraved, because a totally depraved man would not say that he is totally depraved.