They are jealous of you. He comes at length to the false apostles, and does more by silence to make them odious, than if he had given their names; for we usually abstain from naming those whose very names produce in us dislike and aversion. He mentions the immoderate ambition of those men, and warns the Galatians not to be led astray by their appearance of zeal. The comparison is borrowed from honorable love, as contrasted with those professions of regard which arise from unhallowed desires. Jealousy, on the part of the false apostles, ought not to impose upon them; for it proceeded not from right zeal, but from an improper desire of obtaining reputation, -- a desire most unlike that holy jealousy of which Paul speaks to the Corinthians. "For I am jealous over you with godly jealousy; for I have espoused you to one husband, that I may present you as a chaste virgin to Christ. But I fear lest by any means, as the serpent beguiled Eve through his subtlety, so your minds should be corrupted from the simplicity that is in Christ." (2-Corinthians 11:2, 3.) To expose still more fully their base arts, he corrects his language. Yea, they would exclude you [1] They not only endeavor to gain your affections, but, as they cannot obtain possession of you by any other means, they endeavor to kindle strife between us. When you have been thrown as it were destitute, they expect that you will yield yourselves up to them; for they perceive that, so long as there shall be maintained between us a religious harmony, they can have no influence. This stratagem is frequently resorted to by all the ministers of Satan. By producing in the people a dislike of their pastor, they hope afterwards to draw them to themselves; and, having disposed of the rival, to obtain quiet possession. A careful and judicious examination of their conduct will discover that in this way they always begin.

Footnotes

1 - 'Esti gar kai zolos agathos hotan tis houto zeloi hoste mimesasthai ten areten; esti kai zolos proneros oste ekballein tos aretos ton katorthounta; ho de kai autoi nun epicheirousi, tos men teleias gnoseos ekballein thelontes, eis de ten ekroteriasmenen humas de tous nun hupseloterous auton ontas, en taxei katastesosi matheton; touto gar edelosen eiton hina autous zeloute "There is a good zeal, when one emulates in such a manner as to imitate virtue; and there is a bad zeal, which drives away' from virtue one who is acting right. And this is what they are now attempting to do, when they wish to drive away' from perfect knowledge, and to lead them to that which is mutilated and spurious, for no other reason than that they may occupy the ranks of teachers, and that you, who are higher than themselves, may be placed by them in the rank of scholars; for this is what he meant by saying, that ye may emulate them.'" -- Chrysostom.

They zealously affect you - See 1-Corinthians 12:31 (Greek); 1-Corinthians 14:39. The word used here (Ζηλόω Zēloō), means to be "zealous" toward, that is, for or against any person or thing; usually, in a good sense, to be eager for. Here it means, that the false teachers made a show of zeal toward the Galatians, or professed affection for them in order to gain them as their followers. They were full of ardor, and professed an extraordinary concern for their welfare - as people always do who are demagogues, or who seek to gain proselytes. The object of the apostle in this is, probably, to say, that it was not wholly owing to themselves that they had become alienated from the doctrines which he had taught. Great pains had been taken to do it; and there had been a show of zeal which would be likely to endanger any person.
But not well - Not with good motives, or with good designs.
Yea, they would exclude you - Margin, "Us." A few printed editions of the New Testament have ἡμᾶς hēmas, "us," instead of ὑμᾶς humas, "you" - Mill. The word "exclude" here probably means, that they endeavored to exclude the Galatians from the love and affection of Paul. They would shut them out from that, in order that they might secure them for their own purposes. If the reading in the margin, however, should be retained, the sense would be clearer. "They wish to exclude us, that is, me, the apostle, in order that they may have you wholly to themselves. If they can once get rid of your attachment to me, then they will have no difficulty in securing you for themselves." This reading, says Rosenmuller, is found "in many of the best codices, and versions, and fathers." It is adopted by Doddridge, Locke, and others. The main idea is clear: Paul stood in the way of their designs. The Galatians were truly attached to him, and it was necessary, in order to accomplish their ends, to withdraw their affections from him. When false teachers have designs on a people, they begin by alienating their confidence and affections from their pastors and teachers. They can hope for no success until this is done; and hence, the efforts of errorists, and of infidels, and of scorners, is to undermine the confidence of a people in the ministry, and when this is done there is little difficulty in drawing them over to their own purposes.
That ye might affect them - The same word as in the former part of the verse, "that ye might zealously affect them" - that is, that ye might show ardent attachment to them. Their first work is to manifest special interest for your welfare; their second, to alienate you from him who had first preached the gospel to you; their object, not your salvation, or your real good, but to secure your zealous love for themselves.

They zealously affect you, but not well - It is difficult for common readers to understand the meaning of these words: perhaps it would be better to translate Ζηλουσιν ὑμας ου καλως, these false teachers endeavor to conciliate your esteem, but not in honest or true principles; they work themselves into your good graces; they wish you to place all your affection upon themselves.
They would exclude you - They wish to shut you out from the affection of your apostle, that you might affect them, ἱνα αυτους ζηλουτε, that you might love them alone, hear them alone, abide by their directions only, and totally abandon him who called you into the grace of the Gospel of Christ. Some MSS. read ἡμας, us, instead of ὑμας, you; they wish to shut us entirely out from among you, that you may receive and believe them alone. The sense is nearly the same but the former appears to be the more authentic reading.

They zealously affect you, (q) [but] not well; yea, they would exclude you, (r) that ye might affect them.
(q) For they are jealous over you for their own benefit.
(r) That they may transfer all your love from me to themselves.

They zealously affect you,.... Or "are jealous of you"; meaning the false apostles, whose names, in contempt, he mentions not, being unworthy to be taken notice of, and their names to be transmitted to posterity. These were jealous of them, not with a godly jealousy, as the apostle was, lest their minds should be corrupted from the simplicity of the Gospel; but they were jealous, lest they should love the apostle more than they, and therefore represented him in a very bad light, and expressed great love and kindness for them themselves:
but not well; their zeal and affection were not hearty, and sincere, and without dissimulation, but were all feigned, were only in word and in tongue, not in deed, and in truth: this zealous affection neither proceeded from right principles, nor with right views; they sought themselves, and their own carnal worldly interest, their own pleasure and profit, and not the good and welfare of the souls of these Galatians:
yea, they would exclude you; that is, either from the apostle, from bearing any love unto, and having any respect for him. What they were wishing and seeking for was to draw off the minds and affections of these persons from him; or they were desirous of removing them from the Gospel of Christ unto another Gospel, and did all they could to hinder them from obeying the truth; and particularly were for shutting them out of their Christian liberty, and bringing them under the bondage of the law; yea, were for separating them from the churches, that they might set up themselves at the head of them. Some copies read "us", instead of "you"; and then the meaning is, that they were desirous of excluding the apostle from their company, and from having any share in their affections, which makes little alteration in the sense: and others, instead of "exclude", read "include"; and which is confirmed by the Syriac version, which renders the word "but they would include you"; that is, either they would include, or imprison you under the law, and the bondage of it; or they would monopolize you, and engross all your love to themselves; and which is also the sense of the Arabic version:
that you might affect them; love them, show respect to them, be on their side, follow their directions, imbibe their doctrines, and give up yourselves wholly to their care, and be at their call and command.

They--your flatterers: in contrast to Paul himself, who tells them the truth.
zealously--zeal in proselytism was characteristic especially of the Jews, and so of Judaizers (Galatians 1:14; Matthew 23:15; Romans 10:2).
affect you--that is, court you (2-Corinthians 11:2).
not well--not in a good way, or for a good end. Neither the cause of their zealous courting of you, nor the manner, is what it ought to be.
they would exclude you--"They wish to shut you out" from the kingdom of God (that is, they wish to persuade you that as uncircumcised Gentiles, you are shut out from it), "that ye may zealously court them," that is, become circumcised, as zealous followers of themselves. ALFORD explains it, that their wish was to shut out the Galatians from the general community, and attract them as a separate clique to their own party. So the English word "exclusive," is used.

They zealously seek you. The false, Judaizing teachers are meant. They showed great zeal for them, but they were not seeking their good.
They would exclude you. Exclude you from the great body of Gentile believers and bind you to their clique.
It is good to be zealously affected. To exhibit zeal and feeling is a good thing. It was good to show this feeling when he was present with them. But now it was changed in respect of himself. It was only when he was present.
My little children. He addresses them very tenderly as their spiritual parent.
Of whom I travail in birth again. He is more than a father; he travails for them as a mother. He had done so when they were converted; he did not now again until they were so matured in Christ that they would cling to the gospel.
I desire to be present. When present (Galatians 4:18) they had shown warm feeling for him. He would now that they were face to face.
To change my voice. To speak, not severely, as a letter would sound, but tenderly.
I stand in doubt. Is perplexed by what he hears, and filled with fears.

They - The judaizing teachers who are come among you. Zealously affect you - Express an extraordinary regard for you. But not well - Their zeal is not according to knowledge; neither have they a single eye to your spiritual advantage. Yea, they would exclude you - From me and from the blessings of the gospel. That ye might affect - Love and esteem them.