" Sometimes it appears there is a hidden guide whose duty is to test people through all sorts of discouraging experiences. Those who pick themselves up after defeat and keep on trying arrive; and the world cries, "Bravo! I knew you could do it!" The hidden guide lets no one enjoy great achievement without passing the persistence test. Those who can't take it simply do not make the grade...
We see the few who take the punishment of defeat as an urge to greater effort. These, fortunately, never learn to accept life's reverse gear. But what we do not see, what most of us never suspect of existing, is the silent but irresistible power which comes to the rescue of those who fight on in the face of discouragement. If we speak of this power at all we call it persistence. p179 "

― Napoleon Hill , Think and Grow Rich!