You can be invincible, if you enter into no contest in which it is not in your power to conquer. Take care, then, when you observe a man honored before others or possessed of great power or highly esteemed for any reason, not to suppose him happy, and be not carried away by the appearance. For if the nature of the good is in our power, neither envy nor jealousy will have a place in us.
 Epictetus, Enchiridion (125). copy citation

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Author Epictetus
Source Enchiridion
Topic appearance jealousy
Date 125
Language English
Reference
Note Translated by George Long
Weblink https://en.wikisource.org/wiki/Encheiridion_of_Epictetus_(George_Long)

Context

“but straightaway make a distinction in your mind and say, None of these things is signified to me, but either to my poor body, or to my small property, or to my reputation, or to my children or to my wife: but to me all significations are auspicious if I choose. For whatever of these things results, it is in my power to derive benefit from it. ==XIX== You can be invincible, if you enter into no contest in which it is not in your power to conquer. Take care, then, when you observe a man honored before others or possessed of great power or highly esteemed for any reason, not to suppose him happy, and be not carried away by the appearance. For if the nature of the good is in our power, neither envy nor jealousy will have a place in us. But you yourself will not wish to be a general or senator or consul, but a free man: and there is only one way to this, to despise (care not for) the things which are not in our power. ==XX== 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.” source