Gregory of Nyssa
Catena Aurea · Lukasevangelium 6
For if ye love them which love you, what thank have ye? for sinners also love those that love them. And if ye do good to them which do good to you, what thank have ye? for sinners also do even the same. And if ye lend to them of whom ye hope to receive, what thank have ye? for sinners also lend to sinners, to receive as much again. But love ye your enemies, and do good, and lend, hoping for nothing again; and your reward shall be great, and ye shall be the children of the Highest: for he is kind unto the unthankful and to the evil. Be ye therefore merciful, as your Father also is merciful.
(Orat. cont. usurar.) But man ought to shun that baneful anxiety with which he seeks from the poor man increase of his money and gold, exacting a profit of barren metals. Hence he adds, And lend, hoping for nothing again, &c. If a man should call the harsh calculation of interest, theft, or homicide, he will not err. For what is the difference, whether a man by digging under a wall become possessed of property, or possess it unlawfully by the compulsory rate of interest?