- People often think of Christian morality as a kind of bargain in which God says, “If you keep a lot of rules I’ll reward you, and if you don’t I’ll do the other thing.” I do not think that is the best way of looking at it. I would much rather say that every time you make a choice you are turning the central part of you, the part of you that chooses, into something a little different from what it was before. And taking your life as a whole, with all your innumerable choices, all your life long you are slowly turning this central thing either into a heavenly creature or into a hellish creature: either into a creature that is in harmony with God, and with other creatures, and with itself, or else into one that is in a state of war and hatred with God, and with its fellow-creatures, and with itself. To be the one kind of creature is heaven: that is, it is joy and peace and knowledge and power. To be the other means madness, horror, idiocy, rage, impotence, and eternal loneliness. Each of us at each moment is progressing to the one state or the other.
That explains what always used to puzzle me about Christian writers; they seem to be so very strict at one moment and so very free and easy at another. They talk about mere sins of thought as if they were immensely important: and then they talk about the most frightful murders and treacheries as if you had only got to repent and all would be forgiven. But I have come to see that they are right. What they are always thinking of is the mark which the action leaves on that tiny central self which no one sees in this life but which each of us will have to endure—or enjoy—forever. One man may be so placed that his anger sheds the blood of thousands, and another so placed that however angry he gets he will only be laughed at. But the little mark on the soul may be much the same in both. Each has done something to himself which, unless he repents, will make it harder for him to keep out of the age next time he is tempted, and will make the rage worse when he does fall into it. Each of them, if he seriously turns to God, can have that twist in the central man straightened out again: each is, in the long run, doomed if he will not. The bigness or smallness of the thing, seen from the outside, is not what really matters.
One last point. Remember that, as I said, the right direction leads not only to peace but to knowledge. When a man is getting better, he understands more and more clearly the evil that is still left in him. When a man is getting worse, he understands his own badness less and less. A moderately bad man knows he is not very good: a thoroughly bad man thinks he is all right. This is common sense, really. You understand sleep when you are awake, not while you are sleeping. You can see mistakes in arithmetic when your mind is working properly: while you are making them you cannot see them. You can understand the nature of drunkenness when you are sober not when you are drunk. Good people know about both good and evil: bad people do not know about either. (Mere Christianity)