There are three kinds of people in the world. The first class is of those who live simply for their own sake and pleasure, regarding Man and Nature as so much raw material to be cut up into whatever shape may serve them. In the second class are those who acknowledge some other claim upon them – the will of God, the categorical imperative, or the good of society – and honestly try to pursue their own interests no further than this claim will allow. They try to surrender to the higher claim as much as it demands, like men paying a tax, but hope, like other taxpayers, that what is left over will be enough for them to live on. Their life is divided, like a soldier's or a schoolboy’s life, into time “on parade” and “off parade”, “in school” and “out of school”. But the third class is of those who can say like St Paul that for them “to live is Christ”. These people have got rid of the tiresome business of adjusting the rival claims of Self and God by the simple expedient of rejecting the claims of Self altogether. The old egoistic will has been turned round, reconditioned, and made into a new thing. The will of Christ no longer limits theirs; it is theirs. All their time, in belonging to Him, belongs also to them, for they are His.Is this not the heart of Mark 7 and John 3 and Luke 15 and 18:9-14 and so many other statements Jesus makes to the religious elite? And 2 Corinthians 4:6 and 1 John 3:9?
And because there are three classes, any merely twofold division of the world into good and bad is disastrous. It overlooks the fact that the members of the second class (to which most of us belong) are always and necessarily unhappy. The tax which moral conscience levies on our desires does not in fact leave us enough to live on. As long as we are in this class we must either feel guilt because we have not paid the tax or penury because we have. The Christian doctrine that there is no “salvation” by works done to the moral law is a fact of daily experience. Back or on we must go. But there is no going on simply by our own efforts. If the new Self, the new Will, does not come at His own good pleasure to be born in us, we cannot produce Him synthetically.
The price of Christ is something, in a way, much easier than moral effort – it is to want Him. It is true that the wanting itself would be beyond our power but for one fact. The world is so built that, to help us desert our own satisfactions, they desert us. War and trouble and finally old age take from us one by one all those things that the natural Self hoped for at its setting out. Begging is our only wisdom, and want in the end makes it easier for us to be beggars. Even on those terms the Mercy will receive us.
Update: See others chime in similarly on the three (not two) ways to live here, here, here, here, and here. I interact with Lewis' essay in this book.