The things in our control are by nature free, unrestrained, unhindered; but those not in our control are weak, slavish, restrained, belonging to others.
 Epictetus, Enchiridion (125). copy citation

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Author Epictetus
Source Enchiridion
Topic rich self-control
Date 125
Language English
Reference
Note Translated by Elizabeth Carter
Weblink http://classics.mit.edu/Epictetus/epicench.html

Context

“Things in our control are opinion, pursuit, desire, aversion, and, in a word, whatever are our own actions. Things not in our control are body, property, reputation, command, and, in one word, whatever are not our own actions.
The things in our control are by nature free, unrestrained, unhindered; but those not in our control are weak, slavish, restrained, belonging to others. Remember, then, that if you suppose that things which are slavish by nature are also free, and that what belongs to others is your own, then you will be hindered. You will lament, you will be disturbed, and you will find fault both with gods and men.” source