Every habit and every faculty is confirmed and strengthened by the corresponding acts, the faculty of walking by walking, that of running by running. If you wish to have a faculty for reading, read; if for writing, write.
“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.”
“Remember that it is not the person who insults you or strikes you who offends you, but your opinion about these things as being offensive. When a man then irritates you, you must know that it is your own opinion which has irritated you.”
AI put this 1877 translation into today's English. Only the wording changed: each rewrite was checked against the original to keep its exact meaning.
Original translation
“Remember that it is not he who reviles you or strikes you, who insults you, but it is your opinion about these things as being insulting. When then a man irritates you, you must know that it is your own opinion which has irritated you.”
Translated by George Long, 1877
“The condition and characteristic of an uninstructed person is this: he never expects from himself profit (advantage) nor harm, but from externals. The condition and characteristic of a philosopher is this: he expects all advantage and all harm from himself.”
― EpictetusDiscourses (Book II, Chapter 18)