Do you wish to be invincible? Then don’t enter into combat with what you have no real control over. Your happiness depends on three things, all of wh… - Epictetus

Your happiness depends on three things, all of which are within your power: your will, your ideas concerning the events in which you are involved, and the use you make of your ideas.

In short, if we observe, we shall find that the animal man is pained by nothing so much as by that which is irrational; and, on the contrary, attracted to nothing so much as to that which is rational.

Everything is estimated by the standard of its own good. The vine is valued for its productiveness and the flavour of its wine, the stag for his speed. We ask, with regard to beasts of burden, how sturdy of back they are; for their only use is to bear burdens. If a dog is to find the trail of a wild beast, keenness of scent is of first importance; if to catch his quarry, swiftness of foot; if to attack and harry it, courage. In each thing that quality should be best for which the thing is brought into being and by which it is judged. And what quality is best in man? It is reason; by virtue of reason he surpasses the animals, and is surpassed only by the gods. Perfect reason is therefore the good peculiar to man; all other qualities he shares in some degree with animals and plants. Man is strong; so is the lion. Man is comely; so is the peacock. Man is swift; so is the horse. I do not say that man is surpassed in all these qualities. I am not seeking to find that which is greatest in him, but that which is peculiarly his own. Man has body; so also have trees. Man has the power to act and to move at will; so have beasts and worms. Man has a voice; but how much louder is the voice of the dog, how much shriller that of the eagle, how much deeper that of the bull, how much sweeter and more melodious that of the nightingale! What then is peculiar to man? Reason. When this is right and has reached perfection, man's felicity is complete. Hence, if everything is praiseworthy and has arrived at the end intended by its nature, when it has brought its peculiar good to perfection, and if man's peculiar good is reason; then, if a man has brought his reason to perfection, he is praiseworthy and has readied the end suited to his nature. This perfect reason is called virtue, and is likewise that which is honourable.

Die Natur hat dem menschen eine Zunge, aber zwei Ohren gegeben, damit er doppelt so viel hört, wie er spricht.