Chapter 10
With every accident, ask yourself what abilities you have for making a proper use of it. If you see an attractive person, you will find that self-restraint is the ability you have against your desire. If you are in pain, you will find fortitude. If you hear unpleasant language, you will find patience. And thus habituated, the appearances of things will not hurry you away along with them.
Upon every accident, remember to turn towards yourself and inquire what faculty you have for its use. If you encounter a handsome person, you will find continence the faculty needed; if pain, then fortitude; if reviling, then patience. And when thus habituated, the phenomena of existence will not overwhelm you.
Epictetus, Enchiridion 10. Translated by Elizabeth Carter (1758). The Stoic Library.