Though you have bestowed a benefit upon me, yet you have since done me a wrong; the benefit demanded gratitude, the wrong required vengeance: the result is that I do not owe you gratitude, nor do you owe me compensation⁠—each is cancelled by the other. When we say, “I returned him his benefit,” we do not mean that we restored to him the very thing which we had received, but something else in its place. To return is to give back one thing instead of another, because, of course, in all repayment it is not the thing itself, but its equivalent which is returned. We are said to have returned money even though we count out gold pieces instead of silver ones, or even if no money passes between us, but the transaction be effected verbally by the assignment of a debt.