Freedom and happiness come from understanding - and working with - our limits. Begin at once a program of self-mastery. Stick with your purpose. Do not seek external approval. Do not worry about anything outside of your control. The only things you command are your thoughts and actions. We choose our response. Stop aspiring to be anyone other than your own best self: for that does fall within your control.
EpictetusWhat really frightens and dismays us is not external events themselves, but the way in which we think about them. It is not things that disturb us, but our interpretation of their significance.
EpictetusAppearances to the mind are of four kinds. Things either are what they appear to be; or they neither are, nor appear to be; or they are, and do not appear to be; or they are not, and yet appear to be. Rightly to aim in all these cases is the wise man's task.
EpictetusTruth is a thing immortal and perpetual, and it gives to us a beauty that fades not away in time, nor does it take away the freedom of speech which proceeds from justice; but it gives to us the knowledge of what is just and lawful, separating from them the unjust and refuting them.
Epictetus