Discovering what Faith is

You may remember I said that the first step towards humility was to realise that one is proud. I want to add now that the next step is to make some serious attempt to practise the Christian virtues. A week is not enough. Things often go swimmingly for the first week. Try six weeks. By that time, having, as far as one can see, fallen back completely or even fallen lower than the point one began from, one will have discovered some truths about oneself. No man knows how bad he is till he has tried very hard to be good. A silly idea is current that good people do not know what temptation means. This is an obvious lie. Only those who try to resist temptation know how strong it is. After all, you find out the strength of the German army by fighting against it, not by giving in. You find out the strength of a wind by trying to talk against it, not by lying down. A man who gives in to temptation after five minutes simply does not know what it would have been like an hour later. That is why bad people, in one sense, know very little about badness. They have lived a sheltered life by always giving in. We never find out the strength of the evil impulse inside us until we try to fight it: and Christ, because He is the only man who never yielded to temptation, is also the only man who knows to the full what temptation means—the only complete realist. Very well, then. The main thing we learn from a serious attempt to practise the Christian virtues is that we fail.
Then comes another discovery. Every faculty you have,
your power of thinking or of moving your limbs from moment to moment, is given you by God. If you devoted
every moment of your whole life exclusively to His service you could not give Him anything that was not in a sense His own already.... When a man has made these two discoveries God can really get to work. It is after this that real life begins. The man is awake now. We can now go on to talk of Faith....
C.S. Lewis, Mere Christianity (1952; Harper Collins 2001) 141-143.