Aristotle, Nicomachean Ethics
H. Rackham, Ed.

It appears that, as justice is of two kinds, one unwritten and the other defined by law, so the friendship based on utility may be either moral¹ or legal. Hence occasions for complaint chiefly occur when the type of friendship in view at the conclusion of the transaction is not the same as when the a relationship was formed. [6] Such a connection when on stated terms is one of the legal type, whether it be a purely business matter of exchange on the spot, or a more liberal accommodation for future repayment,² though still with an agreement as to the quid pro quo; and in the latter case the obligation is clear and cannot cause dispute, though there is an element of friendliness in the delay allowed, for which reason in some states there is no action at law in these cases, it being held that the party to a contract involving credit must abide by the consequences. [7] The moral type on the other hand is not based on stated terms, but the gift or other service is given as to a friend, although the giver expects to receive an equivalent or greater return, as though it had not been a free gift but a loan; and as he ends the relationship in a different spirit from that in which he began it, he will complain.³ [8] The reason of this is that all men, or most men, wish what is noble but choose what is profitable; and while it is noble to render a service not with an eye to receiving one in return,