A good tree cannot bring forth evil fruit, neither can an evil tree bring forth good fruit.

“We would ask those heretics who affirm that there are two natures directly opposed to each other, if they admit that a good tree cannot bring forth evil 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?”

“(Serm. in Mont. ii. 25.) 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.”

“He teaches the precautions against which one must be on guard. Now they are described from their profession, since they are prophets. But it can be asked, of which prophets, since the Law and the Prophets extend up to John: hence at that time there were no prophets concerning Christ, since they come to an end in him. Therefore it must be said that the prophets here are the teachers and prelates in the Church. But what is meant by his calling them false? Those are called false who are not sent. Of such it is said, Jeremiah 23:21: "I did not send them, and they ran." Likewise those are called false who speak a lie; hence Jeremiah 2:8: "their prophets prophesied in Baal." Thus too there were many false prophets among the people, just as among us too there will be lying teachers. "Attend," that is, diligently beware, because they are hidden, and one must beware of hidden snares. Hence their malice lies hidden within. He says therefore: "who come to you in the clothing of sheep," etc. Sheep are the faithful: "but we are his people, and the sheep of his pasture," Psalm 99:3. But their clothing is fasting and almsgiving, with which they cover themselves; 2 Timothy 3:5: "having the appearance of piety, but denying its power." But it must be known that if wolves cover themselves with the skins of sheep, the sheep does not for this reason lose its own skin: so, although those evil men are covered with good works, still much good is accomplished. But "within they are ravenous wolves." This is expounded chiefly of heretics, and consequently of evil prelates. Hence it is said, on that text of John 10:11, "I am the good shepherd," that one man is a shepherd, who governs and rules; another is a wolf, who intends destruction; another is a hireling, who seeks his own advantage. Hence the shepherd is to be loved, the wolf to be fled, the hireling to be tolerated. What is said, then — "but within they are ravenous wolves" — is understood of those who have the intention of perverting the people, and these must be called wolves. Likewise hirelings, namely evil Christians, who scatter the flock by bad example, who have an evil life; as to their effect, they have the manner of a wolf; Acts 20:29: "for after my departure ravenous wolves will enter in among you, not sparing the flock," etc. And he says "within," because they have an evil intention of killing the people. "By their fruits you shall know them," etc. "By their fruits," that is, by their works. But this seems to be against the point, because they also have the clothing of sheep, and clothing too is a work; therefore they would be known by these as well. Chrysostom: the fruit is the confession of the faith. Hence if one confesses the faith, he is not a heretic. Ephesians 5:9: "for the fruit of light is in all goodness, and justice, and truth," etc. But if it is expounded of hypocrites, then it is expounded thus, that by "clothing" are meant exterior works. Hence Galatians 5:22: "but the fruit of the Spirit is charity, joy, and peace," etc. But you might ask: how can they be known? It must be said that scarcely can any hypocrite be so composed that something of malice does not appear either in word or in deed: Proverbs 27:19: "as in water the faces of those who look in shine back, so the hearts of men are manifest to the prudent." And Seneca: "no one can long bear a feigned mask." Now they are made manifest chiefly in two ways: in those things which must be done suddenly, since in those things which one does with deliberation he is on his guard; likewise in tribulations; Ecclesiasticus 6:8: "there is a friend for his own time, and he will not remain in the day of tribulation." Likewise they are made manifest when they cannot have what they wish, or when they have already obtained it — hence "power reveals the man." "Do men gather grapes from thorns?" By grapes, from which wine is made, is understood spiritual joy, because "wine gladdens the heart of man," Psalm 103:15. By figs is meant the sweetness of ecclesiastical peace, which is charity. These cannot be born from briers, that is, from sinners, because "thorns and briers it shall bring forth for you," Genesis 3:18. And he proves this by an example: "every good tree bears good fruits, but a bad tree bears bad fruits." From this the Manicheans assumed two natures, namely a good one and an evil one. But this is not true, because we see good fruit come from an evil creation, and the converse. Hence for this you should understand that the tree is the principle of the fruit. But the principle is twofold: a principle of nature, and a principle of moral conduct. The principle of nature is the soul, and whatever proceeds from it naturally is wholly good. But the principle of moral conduct is the will; therefore if the will is good, the work too is good, provided it has a good will together with a good intention — for if someone wished to steal in order to give alms, even though the will is good, the intention nonetheless is not right. But what will become of the bad tree? "Every tree which does not bear fruit will be cut down": because if it does not bear fruit, or if it fails to bear it when it could, it will be cut down; hence John 15:6: "if anyone does not remain in me, he shall be cast out as a branch, and shall wither, and they shall gather him and cast him into the fire, and he burns." Hence in Luke 13:7 it is said of the fig tree, which the lord commanded to be cut down and removed: "let the impious man be taken away, lest he see the glory of God." He concludes therefore: "by their fruits you shall know them." "Not everyone who says to me, Lord, Lord," etc. Having set forth the teaching, he shows that it must be observed, because nothing else suffices for salvation. And concerning the commandments, or the teaching of God, four things are necessary, or praiseworthy: that we confess with the mouth, that it be confirmed by miracles, that the word of God be heard, and that it be carried out in deed. Concerning the first, Romans 10:10: "with the heart one believes unto justice, but with the mouth confession is made unto salvation." Concerning the second, Mark, last chapter, 20: "the Lord cooperating, and confirming the word by the signs that followed." Likewise, that it be heard; John 8:47: "he who is of God hears the words of God." Likewise, fourth, it is required that one do it; James 1:22: "be doers of the word, and not hearers only." Hence he wishes to show that the three without the fourth do not profit; hence he says: "not everyone who says to me, Lord, Lord," etc. But this seems contrary to the Apostle, who says: "no one can say, Lord Jesus, except in the Holy Spirit." But whoever has the Holy Spirit enters into the kingdom of heaven. Augustine resolves this, saying that "to say" is spoken in many ways: commonly, and strictly, and properly. Strictly it is nothing other than to manifest affection and will; and it is in this sense that the Apostle says: "no one can say, Lord Jesus, except in the Holy Spirit," etc. And this is nothing other than to believe the Lord, and to obey him. Commonly, however, it means to proclaim in whatever way with the mouth; concerning which we have Jeremiah 26:13: "this people honors me with their lips, but their heart is far from me." Or it may be taken thus. "Not everyone who says to me, Lord, Lord," etc. He repeats this word, "Lord, Lord," to signify that confession is twofold, namely of voice and of praise, neither of which suffices by itself. Hence Isaiah 26:13: "this people honors me with their lips, but their heart is far from me." Who then shall enter? Not he who says "Lord, Lord," but he who has done the will of my Father, etc. John 3:13: "no one ascends into heaven, except he who descended from heaven," etc. Hence no one can ascend, unless he descends as Christ did, of whom it is said, John 6:38: "I descended from heaven, not to do my own will, but the will of him who sent me." Hence one must do the will of God; 1 Thessalonians 4:3: "for this is the will of God, your sanctification." Hence David said, Psalm 142:10: "teach me to do your will." And likewise, just as the Lord taught us to pray, "your will be done." But it must be noted that by his saying "kingdom," eternal reward is touched upon; hence he says "shall enter." For that kingdom consists in spiritual goods, not in exterior goods; therefore he says "shall enter." Hence Song of Songs 1:4: "the king brought me into his storerooms." Likewise he says "of heaven," because although someone here has riches, or honors, all this is for the sake of that kingdom. Hence the reward shall be among the lofty things. But someone might say that working miracles suffices for salvation. This he excludes, because "many will say to me on that day: Lord, Lord, have we not prophesied in your name?" etc. And he says "many," signifying those who withdraw from unity, because they are under multitude, for "the number of fools is infinite," Ecclesiastes 1:15. Likewise he brings this in for the understanding of what he had said, that "every tree which does not bear fruit will be cut down." And he had not said by whom; therefore he said "to me," as to the judge appointed, because "the Father has given all judgment to the Son," John 5:22. Likewise he says "on that day." "Day" names the term, but not according to the quality of time, because the day of judgment is sometimes called night, and sometimes it is called day, sometimes night, because it is uncertain when it will come. Hence below, 25:6: "at midnight a cry was made: behold, the bridegroom comes, go forth to meet him." The Apostle calls it "day," 1 Corinthians 4:3. And in Psalm 36:6: "and he will bring forth your justice as the light, and your judgment as the noonday." "Lord, Lord." He repeats it to signify greater confusion and fear; Wisdom 5:2: "for they shall be troubled with horrible fear." "Have we not cast out demons in your name?" This is supernatural power; Job 41:24: "for there is no power upon earth that can be compared to this," namely, to the power of the Devil. But then it is asked how those who cast out demons become reprobate. Chrysostom answers that these men are lying. Another answer is that at one time they were good, and worked miracles, and afterward became evil. But this cannot stand, because the Lord says, "I never knew you." In another way it must be said that they say "in your name," not in the name of the Holy Spirit; for some act in the power of the Holy Spirit, some not. For as we have it, Jeremiah 2:8, some prophesied in the name of Baal; likewise some act through magic arts. But it is asked how demons work miracles. I say that they cannot; but they do certain things which appear to be miracles, though they are not miracles. Those things are called miracles when the effects are evident but the causes are hidden. Hence there can be something wondrous to those who are less learned, which is not wondrous to the wise, as is clear in the case of an eclipse. Hence, since demons know natural things in a truer way, they can do things which seem to us to be miracles. Otherwise, according to Jerome: because, as he says, among the gifts of the Holy Spirit there are some which are given freely; charity alone is that which distinguishes between the sons of God and the sons of the Devil; 1 Corinthians 12:7: "to each one is given the manifestation of the Spirit for usefulness," or for the profit of his own goodness, or of the Church, so that the faith which he preaches may be made manifest. And thus too sometimes a prelate living wickedly can work miracles. And then "I will declare to them, that I never knew you," that is, I did not approve, not even when you were working miracles; 2 Timothy 2:19: "the Lord knows who are his." He says "I never knew you," when he says "depart from me," because you were never approved. "Everyone therefore who hears," etc. He shows that without works nothing suffices, not even the hearing of the word of God, because hearing is ordered to faith. Romans 10:17: "but faith is from hearing." For hearing does not suffice. And he shows this in two ways, for he sets forth, under a comparison, the outcome of him who hears and does, and of him who hears and does not do. And first he does three things: first he sets down the building; second, the assault, at "and the rain came down," etc.; third, the immutability, at "and it did not fall," etc. He says therefore that hearing does not suffice; for hearing is necessary — John 8:47: "he who is of God hears the words of God" — but it does not suffice; Romans 2:13: "for not the hearers of the law but the doers shall be justified." Likewise he says well, "these my words," because whatever pertains to salvation is contained there. Hence "he who hears these words, and does them, shall be likened to a wise man." And he does not say that he is wise, but that he "shall be likened." This comparison can be understood of a bodily builder, and thus the letter is plain. Or it can be understood spiritually, and thus this man is Christ. Ecclesiastes 7:29: "one man out of a thousand I have found." The house of Christ is the Church, for he knows how it must be built. Hence concerning him, Proverbs 9:1: "wisdom has built herself a house." And Proverbs 14:1: "a wise woman builds her house." "Upon the rock"; 1 Corinthians 10:1: "and the rock was Christ." Hence Christ builds upon himself, for he himself is the foundation; hence 1 Corinthians 3:11: "no other foundation can anyone lay besides that which has been laid, which is Christ Jesus." For this is the foundation of eternal truth. And this is altogether immovable; Psalm 124:4: "they who trust in the Lord are like Mount Sion." There follows the assault upon this house: "and the rain came down." By rain is understood teaching, and there is good rain, and bad rain. The rain, therefore, which rushes in, is bad teaching; Genesis 19:24: "the Lord rained upon Sodom sulphur and fire." Likewise "rivers" are good, and not good; Isaiah 18:2: "the rivers have wasted his land"; and by this are signified the wise who consider themselves to be wise. These rivers are generated from the rains. By "winds" are meant demons. Hence in the canonical epistle of Jude, verse 12: "clouds without water, which are carried about by winds," etc. "And they rushed against the house," that is, against the Church, "and it did not fall." "For its cords shall not be broken forever," Isaiah 33:20. And why? "It was founded upon the rock," that is, upon Christ. Next he sets forth the comparison, setting down the outcome of him who hears and does not do; and concerning this he first sets down the building; second, the assault, at "and the rain came down," etc.; third, the ruin, at "and it fell," etc. He says: "and everyone who hears these my words, and does not do them, shall be like a foolish man," who has fallen from the light of wisdom. Hence Ecclesiastes 4:13: "better is a wise servant than an old and foolish king." Likewise the fool is the Devil. The house which he builds is the congregation of the unfaithful; hence Psalm 73:30: "the earth is filled with houses of iniquity." And this man builds "upon sand." By sand are meant the unfaithful, who are unfruitful. Likewise, on account of their great number: for "the number of fools is infinite," Ecclesiastes 1:15. Likewise sand does not cohere, so these men are always at strife. He founds, therefore, upon sand, that is, upon an end which is, as it were, a foundation, namely he fixes his intention upon a temporal good. "The rain came down," that is, bad teaching came; "the rivers came," that is, false teachers; "the winds blew," that is, angels — Psalm 103:4: "who makes his angels spirits." "And they rushed against that house, and it fell." Apocalypse 14:8: "fallen, fallen is Babylon," namely through preaching. "And great was its fall." If we wish to adapt the comparison, it must be said thus, that a man ought to build as Christ built. And this the Apostle teaches, 1 Corinthians 3:10: "let each one see how he builds upon it." For one man builds a dwelling place of God; another, on the contrary, as below is stated, and as we have it in 1 Corinthians 3:12, some build upon stubble. For the foundation is that upon which someone places his intention. For some hear in order to know, and these build upon the intellect, and this is building upon sand; hence James 1:23: "he who hears, and does not do, is like a man beholding the face of his birth in a mirror." Hence they build upon what is changeable. But another hears in order to do and to love, and this man builds upon the rock, because upon what is firm and stable; Proverbs 22:6: "a young man according to his way, even when he is old, will not depart from it." For this foundation rests upon charity. The Apostle, Romans 8:35: "who shall separate us from the charity of Christ?" But here it can be asked why the foundation which is in the intellect is unstable and not firm, while that which is in the affection is firm. The reason is that the intellect deals with universals, for it cannot know many things except in a universal way; therefore, wandering about the universal, it has no stability; but operations and affections concern particulars, and concern a good habit; therefore if temptation comes, one clings to that to which he is accustomed, namely to a good operation, and so he resists. But then it is asked what he means by "rain." It must be said, then, that the Devil never tempts first in greater things, but first in lesser things, and then proceeds to greater ones. Hence by "rain" is meant a depraved thought. He tempts, therefore, in a depraved thought, and if one consents, he then tempts him in something greater, and thus it is afterward increased. And from these come the "rivers," and afterward he rushes in with all his strength, and the man necessarily falls; Ecclesiasticus 19:1: "he who despises small things shall fall little by little." Or thus: "rain" is the temptation of the flesh; "rivers," the temptation of the world; "winds," the temptation of the Devil. Or, according to Augustine, "rain" is superstitious teaching, clinging to which one falls most gravely, and this is made a great fall; but it is not great when one merely stumbles and does not fall, because when temptation occurs, he fears and grieves. But some fall entirely; Psalm 136:7: "raze it, raze it, even to its foundation." Or it is called "a great fall" because the heart is impenitent; Job 21:13: "they spend their days in good things, and in a moment they go down to hell." "And it came to pass, when Jesus had finished these words, the crowds were astonished." The effect is set down. For there was a threefold manner of men who followed the Lord Jesus. Some indeed were astonished and were scandalized, as the Pharisees, concerning whom see below, chapter 15. Some were astonished, but were not scandalized, as the crowds. Some indeed, as the perfect, were not astonished at all. But it must be asked concerning this, why he says "the crowds," since the crowds were not there. And it can be said that the sermon was addressed both to the crowds and to the disciples; but on the mountain, beneath the summit of the mountain, there was a certain plain. The disciples, therefore, were on the summit with Christ, but the crowds were on the plain. Or it can be said that it was addressed first to the disciples, and afterward to the crowds. Or it can be said: crowds of disciples followed him. But what was the reason for their astonishment? Because "he was teaching them as one having power." Hence in him is fulfilled what is said, Ecclesiastes 8:4: "his word is full of power." Hence, as "one having power," because he spoke as the Lord, or as a lawgiver. Or, as "having power," with the power of penetrating the heart. Hence it is said, Psalm 67:34: "he will give to his voice the voice of power." Or with the power of working miracles, because what he said, he confirmed by miracles. Augustine says that all the things which are said in this sermon must be reduced to the seven gifts, and to the beatitudes, because that which is first said, "you shall not kill," pertains to the gift of fear, and to the beatitude of poverty. That which follows next, "be agreeable with your adversary," pertains to the gift of piety, through which meekness is fulfilled. That, "you shall not commit adultery," etc., pertains to the gift of knowledge, through which the beatitude of mourning is fulfilled. That concerning enduring wrongs pertains to the gift of fortitude, by which is fulfilled also the beatitude of those who are blessed who hunger and thirst for justice, etc. That which is said, "love your enemies," pertains to the gift of counsel, by which the beatitude of mercy is fulfilled. And through that which follows in chapter 6, concerning not having anxiety, up to "enter through the narrow gate," he intends to cleanse the heart; hence it pertains to the gift of understanding, and to the beatitude which is purity of heart; hence, "blessed are the pure in heart, for they shall see God." But whatever follows pertains to the gift of wisdom.”

“Wherefore by their fruits ye shall know them. This is the conclusion of the whole, and a repetition of what is before said, the more to fix the rule of judgment upon their minds, and engage them to try men by their doctrines, and their doctrines by the standard of the Scriptures, and not believe every spirit; for with some care and diligence such persons may be detected, and the malignant influence of their ministry be prevented. The sum of the whole is, that ordinarily, and generally speaking, as men are, so are the doctrines they preach, and by them they may be known, and judged to be what they are. Christ here, and in the preceding verses, is speaking not of men of bad lives and conversations, who take upon them to teach others; for there is not so much reason to caution good men against these; they are easily detected, and generally discarded; but of men that put on sheep's clothing, who pretended to much holiness of life and conversation, and strictness of religion; and under that disguise delivered out the most corrupt and unwholesome doctrines; which tended greatly to depreciate him and his grace, and to do damage to the souls of men. Wherefore by their fruits ye shall know them. This is the conclusion of the whole, and a repetition of what is before said, the more to fix the rule of judgment upon their minds, and engage them to try men by their doctrines, and their doctrines by the standard of the Scriptures, and not believe every spirit; for with some care and diligence such persons may be detected, and the malignant influence of their ministry be prevented. The sum of the whole is, that ordinarily, and generally speaking, as men are, so are the doctrines they preach, and by them they may be known, and judged to be what they are. Christ here, and in the preceding verses, is speaking not of men of bad lives and conversations, who take upon them to teach others; for there is not so much reason to caution good men against these; they are easily detected, and generally discarded; but of men that put on sheep's clothing, who pretended to much holiness of life and conversation, and strictness of religion; and under that disguise delivered out the most corrupt and unwholesome doctrines; which tended greatly to depreciate him and his grace, and to do damage to the souls of men. Matthew 7:21 mat 7:21 mat 7:21 mat 7:21Not everyone that saith unto me Lord, Lord,.... Not every one that calls Christ his Lord and Master, professes subjection to him, or that calls upon his name, or is called by his name; or makes use of it in his public ministrations. There are many who desire to be called, and accounted Christians, and who make mention of the name of Christ in their sermons, only to take away their reproach, to cover themselves, and gain credit with, and get into the affections and goodwill of the people; but have no hearty love to Christ, nor true faith in him: nor is it their concern to preach his Gospel, advance his glory, and promote his kingdom and interest; their chief view is to please men, aggrandize themselves, and set up the power of human nature in opposition to the grace of God, and the righteousness of Christ. Now not everyone of these, no, not any of them, shall enter into the kingdom of heaven. This is to be understood not of the outward dispensation of the Gospel, or the Gospel church state, or the visible church of Christ on earth, in which sense this phrase is sometimes used; because such persons may, and often do, enter here; but of eternal glory, into which none shall enter, but he that doeth the will of my Father which is in heaven. This, as it may regard private Christians, intends not merely outward obedience to the will of God, declared in his law, nor barely subjection to the ordinances of the Gospel; but more especially faith in Christ for life and salvation; which is the source of all true evangelical obedience, and without which nothing is acceptable to God. He that seeth the Son, looks unto him, ventures on him, commits himself to him, trusts in him, relies on him, and believes on him for righteousness, salvation, and eternal life, he it is that does the will of the Father, and he only; and such an one, as he is desirous of doing the will of God in all acts of cheerful obedience to it, without dependence thereon; so he shall certainly enter the kingdom of heaven, and have everlasting life; see Joh 6:40 but as these words chiefly respect preachers, the sense of them is this, that only such who are faithful dispensers of the word shall enter into the joy of their Lord. Such do the will of Christ's Father, and so his own, which are the same, who fully and faithfully preach the Gospel of the grace of God; who declare the whole counsel of God, and keep back nothing that is profitable to the souls of men; who are neither ashamed of the testimony of Christ, nor afraid of the faces of men; but as they are put in trust with the Gospel, so they speak it boldly, with all sincerity, not as pleasing men, but God, and commend themselves to every man's conscience in the sight of God: such as these shall have an abundant entrance into the kingdom and glory of God. The Vulgate Latin adds this clause, "he shall enter into the kingdom of heaven", and so does Munster's Hebrew edition of the Gospel according to Matthew.”

“A good tree cannot yield bad fruit, &c. Not but that both good and bad men may change their lives. This, according to the unanimous consent of the Fathers, is only to be understood while they remain such. If a bad tree begin to produce good fruit, it becomes a good tree, &c. (Witham) — For not those who do one or two good works are just, but those who continue permanently to do good: in the same manner, not those who commit one or two bad actions are wicked, but those who continue in evil. (Menochius)”

“A good tree cannot bring forth evil fruit, neither can a corrupt tree bring forth good fruit--Obvious as is the truth here expressed in different forms--that the heart determines and is the only proper interpreter of the actions of our life--no one who knows how the Church of Rome makes a merit of actions, quite apart from the motives that prompt them, and how the same tendency manifests itself from time to time even among Protestant Christians, can think it too obvious to be insisted on by the teachers of divine truth. Here follows a wholesome digression.”