"A man does not always say to himself, 'Hullo! I'm growing up.' It is often only when he looks back that he realises what has happened and recognises it as what people call 'growing up.' You can see it even in simple matters. A man who starts anxiously watching to see whether he is going to sleep is very likely to remain wide awake. As well, the thing I am talking of now may not happen to everyone in a sudden flash--as it did to St Paul or Bunyan: it may be so gradual that no one could ever point to a particular hour or even a particular year. And what matters it the nature of the change in itself, not how we feel while it is happening. It is the change from being confident about our own efforts to the state in which we despair of doing anything for ourselves and leave it to God.
I know the words 'leave it to God' can be misunderstood, but they must stay for a moment. The sense in which a Christian leaves it to God is that he puts all his trust in Christ: trusts that Christ will somehow share with him the perfect human obedience which He carried out from His birth to His crucifixion: that Christ will make the man more like Himself and, in a sense, make good his deficiencies."