'After each failure, ask forgiveness, pick yourself up, and try again. Very often what God first helps us towards is not virtue itself but just this power of always trying again. For however important chastity (or courage, or truthfulness, or any other virtue) may be, this process trains us in habits of the soul which are more important still. It cures our illusions about ourselves and teaches us to depend on God. We learn, on the one hand, that we cannot trust ourselves even in our best moments, and, on the other, that we need not despair even in the worst, for our failures are forgiven. The fatal thing is to sit down content with anything less than perfection.'
CS Lewis, Mere Christianity, p.101.
