The most useful piece of learning for the uses of life is to unlearn what is untrue.
As iron is eaten away by rust, so the envious are consumed by their own passion.
The most necessary learning is that which unlearns evil.
Pay attention to your enemies, for they are the first to discover your mistakes.
There are only two people who can tell you the truth about yourself - an enemy who has lost his temper and a friend who loves you dearly.
Wealth and poverty do not lie in a man's estate, but in men's souls.