The Enchiridion (1-2)

There are things which are within our power, and there are things which are beyond our power. Within our power are opinion, aim, desire, aversion, and, in one word, whatever affairs are our own. Beyond our power are body, property, reputation, office, and, in one word, whatever are not properly our own affairs.

Now, the things within our power are by nature free, unrestricted, unhindered; but those beyond our power are weak, dependent, restricted, alien. Remember, then, that if you attribute freedom to things by nature dependent, and take what belongs to others for your own, you will be hindered, you will lament, you will be disturbed, you will find fault both with gods and men. But if you take for your own only that which is your own, and view what belongs to others just as it really is, then no one will ever compel you, no one will restrict you, you will find fault with no one, you will accuse no one, you will do nothing against your will; no one will hurt you, you will not have an enemy, nor will you suffer any harm.

Aiming therefore at such great things, remember that you must not allow yourself any inclination, however slight, towards the attainment of the others; but that you must entirely quit some of them, and for the present postpone the rest. But if you would have these, and possess power and wealth likewise, you may miss the latter in seeking the former; and you will certainly fail of that by which alone happiness and freedom are procured.

Seek at once, therefore, to be able to say to every unpleasing semblance, You are but a semblance and by no means the real thing. And then examine it by those rules which you have; and first and chiefly, by this: whether it concerns the things which are within our own power, or those which are not; and if it concerns anything beyond our power, be prepared to say that it is nothing to you.

Remember that desire demands the attainment of that of which you are desirous; and aversion demands the avoidance of that to which you are averse; that he who fails of the object of his desires is disappointed; and he who incurs the object of his aversion is wretched. If, then, you shun only those undesirable things which you can control, you will never incur anything which you shun; but if you shun sickness, or death, or poverty, you will run the risk of wretchedness. Remove [the habit of] aversion,

then, from all things that are not within our power, and apply it to things undesirable, which are within our power. But for the present altogether restrain desire; for if you desire any of the things not within our own power, you must necessarily be disappointed; and you are not yet secure of those which are within our power, and so are legitimate objects of desire. Where it is practically necessary for you to pursue or avoid anything, do even this with discretion, and gentleness, and moderation.