Don't hope that events will turn out the way you want, welcome events in whichever way they happen: this is the path to peace. - Epictetus

Whoever yields to fate becomes wise, by learning the laws of heaven. — Euripides

First to those universal principles I have spoken of: these you must keep at command, and without them neither sleep nor rise, drink nor eat nor deal with men: the principle that no one can control another's will, and that the will alone is the sphere of good and evil.

There is but one way to tranquility of mind and happiness, and that is to account no external things thine own, but to commit all to God.