He who began a good work...

On the one hand, God's demand for perfection need not discourage you in the least in your present attempts to be good, or even in your present failures. Each time you fall He will pick you up again. And He knows perfectly well that your own efforts are never going to bring you anwhere near perfection. On the other hand, you must realise from the outset that the goal towards which He is beginning to guide you is absolute perfection; and no power in the whole universe, except you yourself, can prevent Him from taking you to that goal. That is what you are in for. And it is very important to realise that. If we do not, then we are very likely to start pulling back and resisting Him after a certain point. C.S. Lewis, Mere Christianity