"There is no substitute for persistence! It cannot be supplanted by any other quality! Remember this in the beginning and it will hearten you when the going may seem difficult and slow.
Those who have cultivated the habit of persistence seem to enjoy insurance against failure. No matter how many times they are defeated, they finally arrive up near the top of the ladder. 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..
Those who can "take it" are bountifully rewarded for their persistence. They receive, as their compensation, whatever goal they are pursuing."
- Napoleon Hill, was an American author who was one of the earliest producers of the modern genre of personal success literature. His most famous work, Think and Grow Rich...