Stoic Wisdom: Epictetus on Envy

Has any man been preferred before you at a banquet, or in being saluted, or in being invited to a consultation? If these things are good, you ought to rejoice that he has obtained them: but if bad, be not grieved because you have not obtained them; and remember that you cannot, if you do not the same things in order to obtain what is not in our power, be considered worthy of the same (equal) things. For how can a man obtain an equal share with another when he does not visit a man's doors as that other man does, when he does not attend him when he goes abroad, as the other man does; when he does not praise (flatter) him as another does? You will be unjust then and insatiable, if you do not part with the price, in return for which those things are sold, and if you wish to obtain them for nothing.  Well, what is the price of lettuces? An obolus perhaps. If then a man gives up the obolus, and receives the lettuces, and if you do not give up the obolus and do not obtain the lettuces do not suppose that you receive less than he who has got the lettuces; for as he has the lettuces, so you have the obolus which you did not give. In the same way then in the other matter also you have not been invited to a man's feast, for you did not give to the host the price at which the supper is sold; but he sells it for praise (flattery), he sells it for personal attention. Give then the price, if it is for your interest, for which it is sold. But if you wish both not to give the price and to obtain the things, you are insatiable and silly.

—Epictetus.  The Enchiridion of Epictetus. Narrative 25. Translated by George Long (1888).