Augustine of Hippo
Catena Aurea · Matthäusevangelium 7
Beware of false prophets, which come to you in sheep’s clothing, but inwardly they are ravening wolves. Ye shall know them by their fruits. Do men gather grapes of thorns, or figs of thistles? Even so every good tree bringeth forth good fruit; but a corrupt tree bringeth forth evil fruit. A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit. Every tree that bringeth not forth good fruit is hewn down, and cast into the fire. Wherefore by their fruits ye shall know them.
(De Civ. Dei, 12. 4.) These men of whom we have spoken are offended with these two natures, not considering them according to their true usefulness; whereas it is not by our advantage or disadvantage, but in itself considered, that nature gives glory to her Framer. All natures then that are, because they are, have their own manner, their own appearance, and as it were their own1 harmony, and are altogether good.