"Difficulties show men what they are. In case of any difficulty remember that God has pitted you against a rough antagonist that you may be a conqueror, and this cannot be without toil." - Epicetus

"It is difficulties that show what men are." - Epicetus, Discourses

"Many things difficult to design prove easy to performance." - Samuel Johnson

"The finest steel has to go through the hottest fire." - Nixon, Richard Milhous