You shall know them by their fruits. Do men gather grapes of thorns, or figs of thistles?
Read Chapter 7
Augustine of Hippo
AD 430
And in [the interpretation of] this passage we must be very much on our guard against the error of those who judge from these same two trees that there are two original natures, the one of which belongs to God, but the other neither belongs to God nor springs from Him. And this error has both been already discussed in other books [of ours] very copiously, and if that is still too little, will be discussed again; but at present we have merely to show that the two trees before us do not help them. In the first place, because it is so clear that He is speaking of men, that whoever reads what goes before and what follows will wonder at their blindness. Secondly, they fix their attention on what is said, A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit, and therefore think that neither can it happen that an evil soul should be changed into something better, nor a good one into something worse; as if it were said, A good tree cannot become evil, no...
As the true Church is known by the four marks of its being one, holy, catholic, and apostolical, so heretics and false teachers are known by certain vices, and the pernicious effects of their novelties in religion. As the true Church is one, by its members submitting with humility to the authority established by Christ, (he that will not hear the Church, let him be unto thee as the heathen and the publican. Matthew xviii. 17.) so are false teachers known by their separation from the ancient Church, and their divisions among themselves, the necessary consequences of rebelling against the authority established by Christ, and alone capable of determining controversies. The same pride and other secret vices which make them despise government, (2 Peter ii. 10.) make them also not afraid to bring in sects of perdition, blaspheming, and this in civil government as well as ecclesiastical. Those that call themselves Reformers, in the beginning of the 16th century, of all others were remarkable ...
It does not seem to me that “false prophets” here refers to the heretics but rather to persons who live morally corrupt lives while wearing a mask of virtue. They are usually called frauds by most people. For this reason Jesus continued by saying, “By their fruits you will know them.” For it is possible to find some virtuous persons living among heretics. But among the corrupted of whom I speak it is in no way possible. “So what difference does it make,” Jesus says in effect, “if even among these false prophets some do put on a hypocritical show of virtue? Certainly they will soon be detected easily.” The nature of this road upon which he commanded us to walk is toilsome and hard. The hypocrite would seldom choose to toil but would prefer only to make a show. For this very reason the hypocrite is easily detected. When Jesus notes that “there are few who find it,” he distinguishes these from those who do not find the way yet pretend to find it. So do not look to the mask but to the beha...
And by the figure of false prophets, here, I think He shadows out not the heretics, but them that are of a corrupt life, yet wear a mask of virtue; whom the generality are wont to call by the name of impostors. Wherefore He also said further,
By their fruits you shall know them. Matthew 7:16
For among heretics one may often find actual goodness, but among those whom I was mentioning, by no means.
What then, it may be said, if in these things too they counterfeit? Nay, they will be easily detected; for such is the nature of this way, in which I commanded men to walk, painful and irksome; but the hypocrite would not choose to take pains, but to make a show only; wherefore also he is easily convicted. Thus, inasmuch as He had said, there be few that find it, He clears them out again from among those, who find it not, yet feign so to do, by commanding us not to look to them that wear the masks only, but to them who in reality pursue it.
But wherefore, one may say, did He not ma...
. The heretics are cunning and deceitful, which is why He says, "Beware." They produce sweet words and feign a decent life, but within lies the hook. "Sheep’s clothing" is meekness, which some pretend to employ, in order to flatter and to deceive. But they are recognized by their "fruit," that is, by their deeds and by their life. For though they can dissemble for a time, they are unmasked by those who are heedful.
