You have bestowed a benefit upon me, yet afterwards you did me an injury; the reward of a benefit should be gratitude, of an injury punishment; but I do not owe you gratitude, nor do you owe me my revenge — the one is absolved by the other. When we say: “I have returned to him his benefit,” we mean that we have returned, not the actual gift that we had received, but something else in its place. For to return is to give one thing in return for another; evidently so, since in every act of repayment we return, not the same object, but the same value. For we are said to have returned money even though we count out gold coins for silver, and, even though no money passes between us, payment may be effected by the assignment of a debt and orally.
I think I hear you saying: “You are wasting your time; for what is the use of my knowing whether the benefit that imposes no obligation remains a benefit. This is like the clever stupidities of lawyers, who declare that one can take possession, not of an inheritance, but only of the objects that are included in the inheritance, just as if there were any difference between an inheritance and the objects that are included in an inheritance.3 Do you, instead, make clear for me this point, which may be of some practical use. When the same man has bestowed on me a benefit, and has afterwards done me an injury, ought I to return to him the benefit, and nevertheless to avenge myself upon him, and to make reply, as it were, on two distinct scores, or ought I to combine the two into one, and take no action at all, leaving the benefit to be wiped out by the injury, and the injury be the benefit? For this is what I see is the practice of our courts; you Stoics should know what the law is in your school. In the courts the processes are kept separate, and the case that I have against another and the case that another has against me are not merged under one formula. If anyone deposits a sum of money in my safekeeping, and the same man afterwards steals something from me, I shall proceed against him for theft, and he will proceed against me for the money deposited.”