The Discourses of Epictetus, tr. by P.E Matheson, , at sacred-texts.com
In everything you do consider what comes first and what follows, and so approach it. Otherwise you will come to it with a good heart at first because you have not reflected on any of the consequences, and afterwards when difficulties come in sight you will shamefully desist.
'I wish to win at the Olympic games.'
'So do I, by the gods, for it is a fine thing.'
Yes, but consider the first steps to it and what follows: and then, if it is to your advantage, lay your hand to the work. You must be under discipline, eat to order, touch no sweets, train under compulsion, at a fixed hour, in heat and cold, drink no cold water, nor wine, except to order; you must hand yourself over completely to your trainer as you would to a physician. Then, when the contest comes, you get hacked, sometimes dislocate your hand, twist your ankle, swallow plenty of sand, get a flogging, and with all this you are sometimes defeated. First consider these things and then enter on the athlete's career, if you still wish to do so: otherwise, look you, you will be behaving like the children, who one day play at athletes, another at gladiators, then sound the trumpet, next dramatize anything they see and admire. You will be just the same—now athlete, now gladiator, then philosopher, then orator, but nothing with all your soul. Like an ape you imitate everything you see, and one thing after another takes your fancy, but nothing that is familiar pleases you, for you undertake nothing with forethought; you do not survey the whole subject and examine it beforehand, but you take it up half-heartedly and at random. In the same way some people when they see a philosopher, and hear some one speaking like Euphrates (and indeed who can speak as he can?) wish to be philosophers themselves.
Man, consider first, what it is you are undertaking: then consider
your own powers, and what you can bear. If you want to be a wrestler, look to your shoulders, your thighs, your loins. For different men are born for different things. Do you suppose that you can be a philosopher if you do as you do now? Do you suppose that you can eat and drink as you do now, and indulge your anger and displeasure just as before? Nay, you must sit up late, you must work hard, conquer some of your desires, abandon your own people, be looked down on by a mere slave, be ridiculed by those who meet you, get the worst of it in everything—in office, in honour, in justice. When you have carefully considered these drawbacks, then come to us, if you think fit: if you are willing to pay this price for peace of mind, freedom, tranquillity. If not, do not come near: do not be like the children, first a philosopher, then a tax-collector, then an orator, then one of Caesar's procurators. These callings do not agree. You must be one man, good or bad: you must develop either your rational soul, or your outward endowments, you must be busy either with your inner man, or with things outside, that is, you must choose between the position of a philosopher and that of an ordinary man.
When Galba was killed some one said to Rufus, 'Now the world is governed by Providence, isn't it?' To which he answered, 'Did I base my proof that the world is governed by Providence upon a casual thing like Galba's death?'