My informant once gave me this phrase as words of encouragement. He told me that he had used it many times for himself when he was faced with some difficult task or situation. He was a singer, and he also acted in plays, and when he was preparing for an audition he would use this phrase to ease his nerves and prepare him for the difficult competition against his peers. My informant did not know the precise origin of the saying, however he mentioned that he remembered that John F. Kennedy recited it in his inauguration address. I believe he used it to express the fact that the road to success for the United States was too long and difficult to expect immediate results, that patience be the key.