Who is there left for me to fear, and over what has he control? Not what is in my power, because no one controls that except myself. As for what is n… - Epictetus

There are things that are within our power, and things that fall outside our power. Within our power are our own opinions, aims, desires, dislikes — in sum, our own thoughts and actions.

It is the act of an ill-instructed man to blame others for his own bad condition; it is the act of one who has begun to be instructed, to lay the blame on himself; and of one whose instruction is completed, neither to blame another, nor himself.

For sheep don’t throw up the grass to show the shepherds how much they have eaten; but, inwardly digesting their food, they outwardly produce wool and milk. Thus, therefore, do you likewise not show theorems to the unlearned, but the actions produced by them after they have been digested.