John Chrysostom
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.
Having taught that the gate is strait, because there are many that pervert the way that leads to it, He proceeds, Take heed of false prophets. In the which that they might be the more careful, He reminds them of the things that were done among their fathers, calling them false prophets; for even in that day the like things fell out.