Snippets from the Handbook 2

Things in our power are by nature free, unhindered, untrammeled; things not in our power are weak, servile, subject to hindrance, dependent on others. 

Remember then that if you imagine that what is naturally slavish is free, and what is naturally another's is your own, you will be hampered, you will mourn, you will be put to confusion, you will blame gods and men. 

But if you think that only your own belongs to you, and that what is another's is indeed another's, no one will ever put compulsion or hindrance on you, you will blame none, you will accuse none, you will do nothing against your will, no one will harm you, you will have no enemy, for no harm can touch you. 

—Epictetus, The Handbook 1