Time in its aging course teaches all things.
Aeschylus

A wise man learns by the mistakes of others,
a fool by his own.
Latin Proverb

The more a man knows, the more he forgives.
Catherine the Great

The man of wisdom is never of two minds;
the man of benevolence never worries;
the man of courage is never afraid.
Confucius

You cannot dream yourself into a character: you must hanmer and forge yourself into one.
Henry D. Thoreau

James Thurber:
Let us not look back in anger or forward in fear, but around in awareness.

James Russell Lowell:
Mishaps are like knives, that either serve us or cut us, as we grasp them by the blade or the handle.