Also see: The Science of Perseverance: How Your Beliefs Can Strengthen (or Weaken) Your Motivation.
Permanence, perseverance and persistence in spite of all obstacles, discouragements and impossibilities: It is this, that in all things distinguishes the strong soul from the weak.
Thomas Carlyle
You may encounter many defeats, but you must not be defeated. In fact, it may be necessary to encounter the defeats, so you can know who you are, what you can rise from, how you can still come out of it.
Maya Angelou
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
Look at a stone cutter hammering away at his rock, perhaps a hundred times without as much as a crack showing in it. Yet at the hundred-and-first blow it will split in two, and I know it was not the last blow that did it, but all that had gone before.
Jacob A. Riis
It’s not that I’m so smart, it’s just that I stay with problems longer.
Albert Einstein