Persistence

Nothing in the world can take the place of Persistence. Talent will not; Nothing is more common than unsuccessful men with talent. Genius will not; Unrewarded genius is almost a proverb. Education will not; The world is full of educated derelicts. Persistence and determination alone are omnipotent. The slogan ‘Press On’ has solved And always will solve the problems of the human race.

Calvin Coolidge (attributed)

*Quote from a program at a Coolidge memorial service (1933); cited in The Oxford Dictionary of Quotations (1999) (per Wikiquotes).