God has entrusted me with myself. No man is free who is not master of himself. A man should so live that his happiness shall depend as little as possible on external things. The world turns aside to let any man pass who knows where he is going.
EpictetusIf you want to improve, be content to be thought foolish and stupid with regard to external things. Don't wish to be thought to know anything; and even if you appear to be somebody important to others, distrust yourself. For, it is difficult to both keep your faculty of choice in a state conformable to nature, and at the same time acquire external things. But while you are careful about the one, you must of necessity neglect the other
Epictetus