A little leaven corrupteth the whole lump.

“For an offender, when he sees any other doing as bad as himself, will be encouraged to do the very same things; and then the wicked one, taking occasion from a single instance, works in others, which God forbid: and by that means the flock will be destroyed. For the greater number of offenders there are, the greater is the mischief that is done by them: for sin which passes without correction grows worse and worse, and spreads to others; since "a little leaven infects the whole lump," and one thief spreads the abomination over a whole nation and "dead flies spoil the whole pot of sweet ointment;" and "when a king hearkens to unrighteous counsel, all the servants under him are wicked." So one scabbed sheep, if not separated from those that are whole, infects the rest with the same distemper; and a man infected with the plague is to be avoided by all men; and a mad dog is dangerous to every one that he touches. If, therefore, we neglect to separate the transgressor from the Church of God, we shall make the "Lord's house a den of thieves."”

“The Apostle has explained according to the teaching, namely, that the yoke of the servitude of the law should not be undergone; here, however, he returns to the first point, showing that they ought to stand firm. And first he sets forth an example of standing; second he removes an impediment to standing, at the words you were running well, etc.; third he assigns the cause of standing, at the words but we, in the Spirit, by faith, etc. Concerning the first he does two things. First he sets forth the example of standing; second he assigns its cause, at the words for in Christ Jesus, etc. He says therefore: those who wish to be justified in the law, Christ profits them nothing, because they fall away from grace. But we — namely, the apostles — stand by hope, because, that is, we await the hope of justice, that is, justice and hope, namely, eternal blessedness. 1 Peter 1:3: he has regenerated us unto a living hope, etc. Or, the hope of justice, that is, Christ, through whom there is for us the hope of justice, because through him we are justified. Philippians 3:20: we await a savior, etc. 1 Corinthians 1:30: who is made unto us wisdom, and justice, and sanctification, and redemption, etc. Or the hope of justice, that is, the hope which is concerning justice, namely, that they be justified not by the law, but by faith. Romans 3:28: we reckon that man is justified by faith without the works of the law. Or the hope of justice, that is, the thing hoped for, toward which justice tends, namely, eternal life. 2 Timothy, last chapter: for the rest, there is laid up for me a crown of justice, etc. And this from faith, because the justice of God is through the faith of Jesus Christ, as is said in Romans 3:22. And this faith indeed is not from man, but from the Holy Spirit who inspires it. Romans 8:15: you have received the spirit of adoption of sons, whereby we cry: Abba, Father, etc. Therefore, just as faith is from the Spirit, so from faith is hope, from hope justice, through which we arrive at eternal life. But this hope does not come from circumcision, nor from being a Gentile, because these things contribute nothing to it. And therefore he says for in Christ Jesus, that is, in those who are in the faith of Christ, neither circumcision nor uncircumcision, etc., that is, they are matters of indifference. But faith — not unformed faith, but that which works through love — James 2:26: faith without works is dead, etc. For faith is a knowledge of the word of God, Ephesians 3:17: that Christ may dwell through faith, etc. And this word is neither perfectly possessed nor perfectly known unless there is also possessed the love which it hopes for. Here there are two doubts concerning the Gloss. The first is, that it says that uncircumcision and circumcision are matters of indifference, whereas above it said if you are circumcised, Christ will profit you nothing. But it must be said that from the genus of the work they are matters of indifference, namely for those who do not place their hope in them; but from the intention of the one acting they are not matters of indifference. For to those who place their hope in them, they are deadly. The second doubt concerns this, that it says that those who do not believe are worse than the demons, since the demons believe and tremble. I respond. It must be said that they are indeed worse as regards the species of the deed, but not as regards the affection. For it displeases the demons that they believe; nor is there so great a wickedness of will in the man who does not believe as there is in the demon who hates what he believes. Consequently, when he says you were running well, etc., he deals with the impediment to standing. And first he sets down the impediment; second he teaches its removal, at the words let no one persuade you, etc. The impediment to their standing was great and harmful; for a thing is harmful in proportion as it deprives one of a greater good. When, therefore, someone is deprived of many spiritual goods, it is a sign that he has had a great impediment. And therefore, that the Apostle might show that they had a great impediment, he reminds them of the spiritual goods which they had lost, when he says you were running well, etc., namely, through the works of faith formed by charity, which spurs one on to run. Psalm 118:32: I have run the way of your commandments, when you enlarged my heart. And this indeed was formerly in you, but while you were thus running, you were hindered, and therefore he adds: who has bewitched you? Concerning which it was spoken above in chapter 3:1; and therefore I pass over it for the present. Who, then, has bewitched you, that is, hindered you from obeying the truth, namely, the evangelical truth? And this he says fittingly; for to obey is a matter of the will applying itself to the consent of one who commands. And therefore faith is a knowledge of the will and of the intellect. It is necessary, therefore, that the will obey faith; and this consists in willing to believe that the grace of the faith of Christ suffices for salvation without the observances of the law. He excludes the impediment, however, when he says let no one, etc., and this from a threefold source. First on the part of themselves; second on the part of God, at the words I am confident, etc.; third on the part of the Apostle, at the words but I, brethren, etc. On the part of themselves, when he says let no one, etc. Here he first shows what is required on their part, that they might avoid this harm, namely, that they no longer consent to any false apostle. 1 Thessalonians 5:5: let us not be of the night, nor of darkness, etc. Ephesians 5:11: have no fellowship with the unfruitful works of darkness, etc., and 2 Timothy 2:17: and their speech spreads like a cancer, etc. From this it is given to understand that they were not yet corrupted, but were being solicited concerning this. Second, he assigns the reason for this when he says for this persuasion, etc. And this is twofold. The first is, that when a man gives himself to someone, he ought to do nothing except what he has judged useful to himself. But you have been handed over to Christ; therefore you ought not to hear or consent except to those things which are from him; therefore this persuasion, by which they wish to send you under the yoke of the law, since it is not from him, namely, from God who called you unto life, but from the devil, insofar, namely, as he is deficient, and therefore you should not consent to them. Or not from him, that is, against him. The second reason is, because it could be said that it is not a great matter if a few consent, since from this there is no danger; and therefore he says that they ought not to consent to them, nor should their snares be despised, but they ought to resist at the beginnings, because a little leaven, etc., that is, those few who are persuading you. Or: this persuasion, small at the beginning, corrupts the whole lump, that is, the congregation of the faithful. Leviticus 2:11: neither shall any leaven or honey be burned in the sacrifice of the Lord. Consequently, when he says I am confident in you, etc., he removes the impediment on the part of God, who supplies help toward this. And he sets down a twofold help: one with respect to those who seduce; the other with respect to those who trouble, at the words but he who troubles you, etc. He says therefore I am confident, etc., as if to say: I have said that you should not consent to a false apostle, and I am confident in you. 2 Corinthians 7:16: I rejoice that in all things I have confidence in you. Hebrews 6:9: but we are confident of you, beloved, better things, and things nearer to salvation. I am confident, I say, in this, namely, that you will taste nothing else than what I have taught you. Above, 1:8: although we, or an angel from heaven, should preach a gospel to you besides that which we have preached, let him be anathema. Philippians 2:2: fulfill my joy, that you may taste the same thing, etc. And this from divine help. And therefore he says in the Lord, namely, God working. 2 Corinthians 3:4: such confidence we have through Christ toward God, etc. Because the Lord will give you to taste according to the sobriety of Catholic truth. Psalm 91: it is good to trust in the Lord, etc. But as to those who trouble, he says but he who troubles, etc., that is, who removes you from the due order, so that, namely, you are turned from spiritual things to bodily things, when the contrary ought to be the case. 1 Corinthians 15:46: not first that which is spiritual, but that which is animal, then that which, etc. And since such an order is perverse, as is said above, 3:3: are you so foolish, that whereas you began in the Spirit, etc., therefore he shall bear the judgment, that is, he shall undergo condemnation. For just as one who leads another to good is rewarded, Daniel 12:3: they who instruct many unto justice, shall shine as stars for all eternity, etc., so one who leads another to evil is condemned. Joshua 7:25: because you have troubled us, may the Lord trouble you this day. Deuteronomy 27:18: cursed be he who makes the blind to wander out of the way. And this, whosoever he be, that is, of whatever authority he be, he shall not be spared. But Porphyry and Julian reproach Paul in this matter for presumption, saying that he says this tearing at Peter — since above he wrote that he had resisted him to his face — so that the meaning would be: whosoever he be, that is, even if it were Peter, he would be punished. But, as Augustine says, it is not to be believed that Paul would speak with a curse concerning the prince of the Church, since it is written in Exodus 22:28: you shall not speak ill of the prince of your people. Nor even that Peter had so offended that he was worthy of condemnation. The Apostle, therefore, speaks of a certain other man who, coming from Judea, said that he had been a disciple of the great apostles, and under that authority, together with other false preachers, was corrupting the Galatians. Above, 2:4: because of false brethren unawares brought in, etc. Consequently, when he says but I, brethren, etc., he removes the impediment on his own part. And first he sets down his own excuse; second the rebuke of those who were defaming him, at the words would that they were cut off, etc. He excludes, however, the falsehood that was imputed to him. And first something pertaining to himself alone; second something pertaining to all, at the words therefore the scandal of the cross is made void, etc. It must be known concerning the first that, the false apostles excusing the Galatians for the fact that they did not keep the legal observances — because they had been so taught by the Apostle — they said that the Apostle had deceived them, and that he had persuaded them to this unto their own servitude; and they confirmed this, saying that Paul had preached in Judea, and had taught that the legal observances ought to be kept. And therefore the Apostle excuses himself concerning this, saying but I, brethren, if I still preach circumcision, as the false apostles impute to me, why do I still suffer persecution? Namely, from the Jews. 1 Corinthians 4:12: we suffer persecution, etc. For the Jews persecuted Paul especially on this account, that he preached that the legal observances ought not to be kept. Acts 21:21, James says to Paul: they have heard of you that you teach a departure from Moses, those of the Jews who are among the Gentiles, saying that they ought not to circumcise their sons, etc. It is plain, therefore, that what they impute to me is not true, otherwise I would not still be suffering persecutions. That which they impute to me is also false through that which is commonly held among others, because if I preach circumcision, the scandal of the cross is made void. For not only I, but also all the apostles, preach Christ crucified, unto the Jews indeed a scandal, etc., as is said in 1 Corinthians 1:23. And they are scandalized most of all at this, that we preach that through the cross of Christ the legal observances are made void. If, therefore, I preach circumcision, the scandal is made void, that is, there will no longer be a scandal among the Jews concerning the cross. For they would patiently endure — indeed, they would gladly wish — that we should preach that the cross and the legal observances ought to be kept together. Or, according to Augustine, the scandal of the cross is made void, that is, the cross, which is the scandal, is made void, as if he were to say: the cross has lost its effect and its power. Above, 2:21: for if justice were by the law, then Christ died in vain. The Apostle, moreover, says specifically the scandal is made void, etc., to give one to understand that it was on this account that the Jews killed Christ, because he did not keep the legal observances, and taught that they were not to be kept. John 9:16: this man is not from God, because he does not keep the sabbath. Consequently he rebukes the false apostles who had defamed him, saying would that they were cut off, etc., as if to say: they themselves trouble you in this, that they wish you to be circumcised; but would that they were not only circumcised, but wholly castrated. But against this, Romans 12:14: bless, and do not curse, etc. To this there is a twofold response. The first is, that the Apostle did not curse them, but rather blessed them, because he wished for them that they be spiritually castrated, that they might keep spiritual chastity, by cutting away the ceremonial observances, according to that saying of Matthew 19:12: there are certain eunuchs, who have castrated themselves for the kingdom of heaven. Second, that he wishes for them the sterility of offspring which eunuchs have, namely, that they not beget. Whence he says would that they were even cut off, etc., that is, that they lose the power of begetting in you, and in others. And this deservedly, because they beget sons unto error, and reduce them into the servitude of the law. Hosea 9:14: give them a womb without children, and dry breasts.”

“I have confidence in you through the Lord,.... Though the apostle had said many things which carried in them the appearance of roughness and severity, yet he still entertained hopes of them that they were not so far gone, but that they might be brought back again; and he here expresses his confidence of it. This confidence in them is not of faith, for no trust is to be put in men; no, not in the best; but of charity, or love, which hopes all things, and believes all things; and which proceeded upon a thorough persuasion he had, that there was some good thing in them; and therefore was confident, that he that had begun the good work would perform it, and not suffer them to be carried away finally and totally with the error of the wicked: and this confidence he had "through the Lord"; either through the Spirit of the Lord, whose office it is to lead into all truth, as it is in Jesus; and who had suggested this to the apostle, and possessed him of this confidence; so that it was not a conjecture and fancy of his, but an intimation from the Spirit of the Lord: or through the Lord Jesus Christ, or "in the Lord", Christ, as the phrase may be rendered; that is, on account of their being in Christ, which the apostle hoped and believed; where they were safe and secure from a final and total seduction; he was confident, that whatever they might seem to be now, things would take a different turn in time: that you will be none otherwise minded; than he was, and they formerly were, when the Gospel was first preached to them, and embraced by them; and particularly in the doctrine of justification by the righteousness of Christ which was the doctrine then called in question, and in debate: but he that troubleth you; he seems to have respect to some particular person, who was the principal of the false teachers, and most famous for his learning, knowledge, gifts, and abilities; and who had done, and was likely to do, the most mischief among them; and was a troubler of God's Israel, and of the pure waters of the sanctuary; he unsettled their minds, and caused them to halt between two, Moses and Christ, law and Gospel, and the doctrines of justification by works, and by the righteousness of Christ; the one being what gave true solid peace and comfort, the other introduced confusion, distress, and fears: the apostle threatens him, and declares that he shall bear his judgment; or condemnation, or damnation, his punishment in this, or the other world; for the judgment, or condemnation, of such that bring in damnable harasses, and pernicious errors, lingereth not, will not be long delayed; and their damnation slumbereth not, but in a little time will seize upon them; when as they have rejected Christ as a sin bearing and atoning Saviour, and his righteousness as the justifying one, they will, agreeably to their own doctrine, be left to bear their punishment themselves, which will be intolerable, and to all eternity; nor shall any escape it, whosoever he be; though ever so knowing and learned, and let his parts and abilities be what they will; or he be ever so famous among men, and cried up as a most excellent preacher.”

“A little leaven leaveneth the whole lump - A proverbial expression, see Co1 5:6, very aptly applied to those who receive the smallest tincture of false doctrine, relative to the things essential to salvation, which soon influences the whole conduct, so that the man becomes totally perverted. They might have argued, "It is a small thing, and should not be made a subject of serious controversy, whether we be circumcised or not." Granted, that in itself it is a small matter; but, as every man who is circumcised is a debtor to do the whole law, Gal 5:3, then your circumcision leads necessarily to your total perversion; as the little portion of leaven, mixed with the batch, soon leavens the whole lump.”

“A little leaven--the false teaching of the Judaizers. A small portion of legalism, if it be mixed with the Gospel, corrupts its purity. To add legal ordinances and works in the least degree to justification by faith, is to undermine "the whole." So "leaven" is used of false doctrine (Mat 16:12 : compare Mat 13:33). In Co1 5:6 it means the corrupting influence of one bad person; so BENGEL understands it here to refer to the person (Gal 5:7-8, Gal 5:10) who misled them. Ecc 9:18, "One sinner destroyeth much good" (Co1 15:33). I prefer to refer it to false doctrine, answering to "persuasion" (Gal 5:8).”