Misfortunes often sharpen the genius.
Ovid

The rays of happiness, like those of light, are colorless when unbroken.
Henry W. Longfellow

Success in the affairs of life often serves to hide one's abilities, whereas adversity frequently gives one an opportunity to discover them.
Horace

Look not mournfully into the past, it comes not back again. Wisely improve the present, it is thine. Go forth to meet the shadowy future without fear and with a manly heart.
Henry Wadsworth Longfellow

A gentleman can withstand hardships; it is only the small man who, when submitted to them, is swept off his feet.
Confucius

Little minds are tamed and subdued by misfortune, but great minds rise above them.
Washington Irving

Difficulties strengthen the mind,
as well as labor does the body.
Seneca

Times of great calamity and confusion have ever been productive of the greatest minds. The purest ore is produced from the hottest furnace, and the brightest thunderbolt is elicited from the darkest storm.
Charles Caleb Colton

The gem cannot be polished without friction, nor man be perfected without trials.
Danish Proverb

Obstacles are great incentives.
Jules Michelet