Here the apostle comes to the body of the epistle; and he begins it with a more general reproof of these churches for their unsteadiness in the faith, which he afterwards, in some following parts of it, enlarges more upon. Here we may observe,

I. How much he was concerned at their defection: I marvel, etc. It filled him at once with the greatest surprise and sorrow. Their sin and folly were that they did not hold fast the doctrine of Christianity as it had been preached to them, but suffered themselves to be removed from the purity and simplicity of it. And there were several things by which their defection was greatly aggravated; as, 1. That they were removed from him that had called them; not only from the apostle, who had been the instrument of calling them into the fellowship of the gospel, but from God himself, by whose order and direction the gospel was preached to them, and they were invited to a participation of the privileges of it: so that herein they had been guilty of a great abuse of his kindness and mercy towards them. 2. That they had been called into the grace of Christ. As the gospel which had been preached to them was the most glorious discovery of divine grace and mercy in Christ Jesus; so thereby they had been called to partake of the greatest blessings and benefits, such as justification, and reconciliation with God here, and eternal life and happiness hereafter. These our Lord Jesus has purchased for us at the expense of his precious blood, and freely bestows upon all who sincerely accept of him: and therefore, in proportion to the greatness of the privilege they enjoyed, such were their sin and folly in deserting it and suffering themselves to be drawn off from the established way of obtaining these blessings. 3. That they were so soon removed. In a very little time they lost that relish and esteem of this grace of Christ which they seemed to have, and too easily fell in with those who taught justification by the works of the law, as many did, who had been bred up in the opinions and notions of the Pharisees, which they mingled with the doctrine of Christ, and so corrupted it; and this, as it was an instance of their weakness, so it was a further aggravation of their guilt. 4. That they were removed to another gospel, which yet was not another. Thus the apostle represents the doctrine of these judaizing teachers; he calls it another gospel, because it opened a different way of justification and salvation from that which was revealed in the gospel, namely, by works, and not by faith in Christ. And yet he adds, “Which is not another—you will find it to be no gospel at all—not really another gospel, but the perverting of the gospel of Christ, and the overturning of the foundations of that”—whereby he intimates that those who go about to establish any other way to heaven than what the gospel of Christ has revealed are guilty of a gross perversion of it, and in the issue will find themselves wretchedly mistaken. Thus the apostle endeavours to impress upon these Galatians a due sense of their guilt in forsaking the gospel way of justification; and yet at the same time he tempers his reproof with mildness and tenderness towards them, and represents them as rather drawn into it by the arts and industry of some that troubled them than as coming into it of their own accord, which, though it did not excuse them, yet was some extenuation of their fault. And hereby he teaches us that, in reproving others, as we should be faithful, so we should also be gentle, and endeavour to restore them in the spirit of meekness, Gal. 6:1.

II. How confident he was that the gospel he had preached to them was the only true gospel. He was so fully persuaded of this that he pronounced an anathema upon those who pretended to preach any other gospel (Gal. 1:8), and, to let them see that this did not proceed from any rashness or intemperate zeal in him, he repeated it, Gal. 1:9. This will not justify our thundering out anathemas against those who differ from us in minor things. It is only against those who forge a new gospel, who overturn the foundation of the covenant of grace, by setting up the works of the law in the place of Christ’s righteousness, and corrupting Christianity with Judaism, that Paul denounces this. He puts the case: “Suppose we should preach any other gospel; nay, suppose an angel from heaven should:” not as if it were possible for an angel from heaven to be the messenger of a lie; but it is expressed so the more to strengthen what he was about to say. “If you have any other gospel preached to you by any other person, under our name, or under colour of having it from an angel himself, you must conclude that you are imposed upon: and whoever preaches another gospel lays himself under a curse, and is in danger of laying you under it too.”