Indeed, a man loses only that which he already has. "I have lost my cloak." Yes, for you had a cloak. "I have a pain in my head." You don't have a pain in your horns, do you? Why, then, are you indignant? For our losses and pains have to do only with the things which we possess.
"But the tyrant will chain--" What? Your leg. "But he will cut off--" What? Your neck. What, then, will he neither chain nor cut off? Your moral purpose. This is why the ancients gave us the injunction, "Know thyself." What follows, then? Why, by the Gods, that one ought to practise in small things, and beginning with them, pass on to the greater. "I have a head-ache." Well, do not say "Alas!" "I have an ear-ache." Do not say "Alas!" And I am not saying that it is not permissible to groan, only do not groan in the centre of your being. And if your slave is slow in bringing your bandage, do not cry and make a wry face and say, "Everybody hates me." Why, who would not hate such a person?
For the future put your confidence in these doctrines and walk about erect, free, not putting your confidence in the size of your body, like an athlete; for you ought not to be invincible in the way an ass is invincible.
Who, then, is the invincible man? He whom nothing that is outside the sphere of his moral purpose can dismay. I then proceed to consider the circumstances one by one, as I would do in the case of the athlete. "This fellow has won the first round. What, then, will he do in the second? What if it be scorching hot? And what will he do at Olympia?"
it is the same way with the case under consideration. If you put a bit of silver coin in a man's way, he will despise it. Yes, but if you put a bit of a wench in his way, what then? Or if it be in the dark, what then? Or if you throw a bit of reputation in his way, what then? Or abuse, what then? Or praise, what then? Or death, what then? All these things he can overcome. What, then, if it be scorching hot--that is, what if he be drunk? What if he be melancholy-mad? What if asleep? The man who passes all these tests is what I mean by the invincible athlete.
(From the Discourses of Epictetus)