If any of you, withdrawing himself from externals, turns to his own faculty of choice, to exercise, and finish, and render it conformable to nature; elevated, free, unrestrained, unhindered, faithful, decent: if he hath learnt too, that whoever desires, or is averse to, things out of his own power, can neither be faithful nor free, but must necessarily be changed and tossed up and down with them; must necessarily too be subject to others, to such as can procure or prevent what he desires or is averse to: if, rising in the morning, he observes and keeps to these rules; bathes and eats as a man of fidelity and honour; and thus, on every subject of action, exercises himself in his principal duty; as a racer, in the business of racing; as a public speaker, in the business of exercising his voice: this is he who truly improves; this is he who hath not wrought in vain.
EPICTETUS. DISCOURSES. Book i. §4. ¶4.