15. Beware of false prophets, which come to you in sheep's clothing, but inwardly they are ravening wolves.
16. You shall know them by their fruits. Do men gather grapes of thorns, or figs of thistles?
17. Even so every good tree brings forth good fruit; but a corrupt tree brings forth evil fruit.
18. A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit.
19. Every tree that brings not forth good fruit is hewn down, and cast into the fire.
20. Wherefore by their fruits you shall know them.
PSEUDO-CHRYS. The Lord had before commanded His Apostles, that they should not do their alms, prayers, and fasting before men, as the hypocrites; and that they might know that all these things may be done in hypocrisy, He speaks saying, Take heed of false prophets.
AUG. When the Lord had said that there were few that find the straight gate narrow way, that heretics, who often commend themselves because of the smallness of their numbers, might not intrude themselves, He straightway subjoins, Take heed of false prophets.
CHRYS. 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 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.
PSEUDO-CHRYS. What is written below that the Law and the Prophets were until John, is said, because there should he no prophecy concerning Christ after He was come. Prophets indeed there have been and are, but not prophesying of Christ, rather interpreting the things which had been prophesied of Christ by the ancients, that is by the doctors of the Churches. For no man can unfold prophetic meaning, but the Spirit of prophecy. The Lord then knowing that there should be false teachers, warns them of divers heresies, saying, Take heed of false prophets. And for as much as they would not be manifest Gentiles, but lurk under the Christian name, He said not 'See you,' but, Take heed. For a thing that is certain is simply seen, or looked upon; but when it is uncertain it is watched or narrowly considered. Also He says Take heed, because it is a sure precaution of security to know him whom you avoid. But this form of warning, Take heed, does not imply that the Devil will introduce heresies against God's will, but by His permission only; but because He would not choose servants without trial, therefore He sends them temptation; and because He would not have them perish through ignorance, He therefore warns them beforehand. Also that no heretical teacher might maintain that He spoke here of Gentile and Jewish teachers and not of them, He adds, who come to you in sheep's clothing. Christians are called sheep, and the sheep's clothing is a form of Christianity and of feigned religion. And nothing so casts out all good as hypocrisy; for evil that puts on the semblance of good, cannot be provided against, because it is unknown. Again, that the heretic might not allege that He here speaks of the true teachers which were yet sinners, He adds, But inwardly they are ravening wolves. But Catholic teachers should they indeed have been sinners, are spoken of as servants of the flesh, yet not as ravening wolves, because it is not their purpose to destroy Christians. Clearly then it is of heretical teachers that He speaks; for they put on the guise of Christians, to the end they may tear in pieces the Christian with the wicked fangs of seduction. Concerning such the Apostle speaks, I know that after my departure there will enter among you grievous wolves, not sparing the flock.
CHRYS Yet He may seem here to have aimed under the title of false prophets, not so much at the heretic, as at those who, while their life is Corrupt, yet wear an outward face of virtuousness; whence it is said, By their fruits you shall know them. For among heretics it is possible many times to find a good life, but among those I have named never.
AUG. Wherefore it is justly asked, what fruits then He would have us look to? For many esteem among fruits some things which pertain to the sheep's clothing, and in this manner are deceived concerning wolves. For they practice fasting, almsgiving, or praying, which they display before men, seeking to please those to whom these things seem difficult. These then are not the fruits by which He teaches us to discern them. Those deeds which are done with good intention, are the proper fleece of the sheep itself, such as are done with bad intention, or in error, are nothing else than a clothing of wolves; but the sheep ought not to hate their own clothing because it is often used to hide wolves. What then are the fruits by which we may know an evil tree? The Apostle says, The works of the flesh are manifest, which are, fornication, uncleanness, &c. And which are they by which we may know a good tree? The same Apostle teaches, saying, The fruits of the Spirit are love, joy, peace.
PSEUDO-CHRYS. The fruits of a man are the confession of his faith and the works of his life; for he who utters according to God the words of humility and a true confession, is the sheep; but he who against the truth howls forth blasphemies against God is the wolf.
JEROME; What is here spoken of false prophets we may apply to all whose dress and speech promise one thing and their actions exhibit another. But it is specially to be understood of heretics, who by observing temperance, chastity, and fasting, surround themselves as it were with a them garment of sanctity,, but in as much as their hearts within are poisoned, they deceive the souls of the more simple brethren
AUG. But from their actions we may conjecture whether this their outward appearance is put on for display. For when by any temptations those things are withdrawn or denied them which they had either attained or sought to attain by this evil, then needs must that it appear whether they be the wolf in sheep's clothing, or the sheep in his own.
GREG. Also the hypocrite is restrained by peaceful ones of Holy Church, and therefore appears clothed with godliness; but let any trial of faith ensue, straight the wolf ravenous at heart strips himself of his sheep's skin, and shows by persecuting how great his rage against the good.
CHRYS And a hypocrite is easily discerned; for the way they are commanded to walk is a hard way, and the hypocrite is loath to toil. And that you may not say that you are unable to find out them that are such, He again enforces what He had said by example from men, saying, Do men gather grapes of thorns, or figs of thistles?
PSEUDO-CHRYS. The grape has in it a mystery of Christ. As the bunch sustains many grapes held together by the woody stem, so likewise Christ holds many believers joined to Him by the wood of the Cross. The fig again is the Church which binds many faithful by a sweet embrace of charity, as the fig contains many seeds enclosed in one skin. The fig then has these significations, namely, love in its sweetness, unity in the close adhesion of its seeds. In the grape is shown patience, in that it is cast into the wine press - joy, because Wine makes glad the heart of man-purity, because it is not mixed with water and sweetness, in that it delights. The thorns and thistles are the heretics. And as a thorn or a thistle has sharp pricks on every part, so the Devil's servants, on whatsoever side you look at them, are full of wickedness. Thorns and thistles then of this sort cannot hear the fruits of the Church. And having instanced in particular trees, as the fig, the vine, the thorn, and the thistle, He proceeds to show that this is universally true, saying, Thus every good tree brings forth good fruit, but an evil tree brings forth evil fruit.
AUG. In this place we must guard against the error of such as imagine that the two trees refer to two different natures; the one of God, the other not. But we affirm that they derive no countenance from these two trees; as it will be evident to any who will read the context that He is speaking here of men.
ID. 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 own harmony, and are altogether good.
CHRYS. But that none should say, An evil tree brings forth indeed evil fruit, but it brings forth also good, and so it becomes hard to discern, as it has a two-fold produce; on this account He adds, A good tree cannot bring forth evil fruit, neither can an evil tree bring forth good fruit.
AUG. From this speech the Manichees suppose that neither can a soul that is evil be possibly changed for better, nor one that is good into worse. As though it had been, A good tree cannot become bad, nor a bad tree become good; whereas it is thus said, A good tree cannot bring forth evil fruit, nor the reverse. The tree is the soul, that is, the man himself; the fruit is the man's works. An evil man therefore cannot work good works, nor a good man evil works. Therefore if an evil man would work good things, let him first become good. But as long as he continues evil, he cannot bring forth good fruits. Like as it is indeed possible that what was once snow, should cease to be so; but it cannot be that snow should be warm; so it is possible that he who has been evil should be so no longer; but it is impossible that an evil man should do good. For though he may sometimes be useful, it is not he that does it, but it comes of Divine Providence superintending.
RABAN. And man is denominated a good tree, or a bad, after his will, as it is good or bad. His fruit is his works, which call neither be good when the will is evil, nor evil when it is good.
AUG. But as it is manifest that all evil works proceed from an evil will, as its fruits from an evil tree; so of this evil will itself whence will you say that it has sprung, except that the evil will of an angel sprung from an angel, of man from man? And what were these two before those evils arose in them, but the good work of good, and praiseworthy nature. See then out of good arises all; nor was there anything at all out of which it might arise but what was good. I mean the evil will itself; since there was no evil before it, no evil works, which could not come but from evil will as fruit from an evil tree. Nor can it be said that it sprung out of good in this way, because it was made good by a good God; for it was made of nothing, and not of God.
JEROME; We would ask those heretics to affirm that there are two natures directly opposed to each other, if they admit that a good tree cannot bring forth fruit, how it was possible for Moses, a good tree, to sin as he did at the water of contradiction? Or for Peter to deny his Lord in the Passion, saying, I know not the man? Or how, on the other hand, could Moses' father-in-law, an evil tree, inasmuch as he believed not in the God of Israel, give good counsel?
CHRYS. He had not enjoined them to punish the false prophets, and therefore shows them the horrors of that punishment that is of God, saying, Every tree that brings not forth good fruit shall be hewn down, and cast into the fire. In these words He seems to aim also at the Jews, and thus calls to mind the word of John the Baptist, denouncing punishment against them in the very same words. For he had thus spoken to the Jews, warning them of the ax impending, the tree that should be cut down, and the fire that could not be extinguished. But if one will examine somewhat closely, here are two punishments, to be cut down, and to be burned; and he that is burned is also altogether cut out of the kingdom; which is the harder punishment. Many indeed fear no more than hell; but I say that the fall of that glory is a far more bitter punishment, than the pains of hell itself. For what evil great or small would not a father undergo, that he might see and enjoy a most dear son? Let us then think the same of that glory; for there is no son so dear to his father as is the rest of the good, to be deceased and to be with Christ. The pain Of hell is indeed intolerable, yet are ten thousand hells nothing to falling from that blessed glory, and being held in hate by Christ.
GLOSS. From the foregoing similitude He draws the conclusion to what He had said before, as being manifest, saying, Therefore by their fruits you shall know them.
Catena Aurea Matthew 7