Enchiridion 20

Bear in mind that it is not the man who reviles or strikes you that insults you, but it is your judgement that these men are insulting you. Therefore, when someone irritates you, be assured that it is your own opinion which has irritated you. And so make it your first endeavour not to be carried away by the external impression; for if once you gain time and delay, you will more easily become master of yourself.

Epictetus, Enchiridion 20, translated by W. A. Oldfather

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. Therefore especially try not to be carried away by the appearance. For if you once gain time and delay, you will more easily master yourself.

Epictetus, Enchiridion 20, translated by George Long

Remember that foul words or blows in themselves are no outrage, but your judgement that they are so. So when any one makes you angry, know that it is your own thought that has angered you. Wherefore make it your first endeavour not to let your impressions carry you away. For if once you gain time and delay, you will find it easier to control yourself.

Epictetus, Enchiridion 20, translated by P. E. Matheson