John Calvin Commentary Galatians 1:7

"which is not another [gospel] only there are some that trouble you, and would pervert the gospel of Christ." — Galatians 1:7 (ASV)

Which is not another thing. Some explain it this way: “though there is not another gospel;” as if it were a sort of correction of the Apostle’s language, to guard against the supposition that there were more gospels than one. Regarding the explanation of the words, I take a simpler view of them, for he speaks contemptuously of the doctrine of the false apostles as being nothing else than a mass of confusion and destruction. As if he had said, “What do those persons allege? On what grounds do they attack the doctrine which I have delivered? They merely trouble you and subvert the gospel. They do nothing more.”

But it amounts to the same meaning, for this, too, I acknowledge, is a correction of the language he had used about another gospel. He declares that it is not a gospel, but a mere disturbance. All I intended to say was that, in my opinion, the word another means another thing. It strongly resembles the common expression, “this amounts to nothing, but that you wish to deceive.”

And wish to pervert. He charges them with the additional crime of doing an injury to Christ by endeavoring to subvert his gospel. Subversion is an enormous crime. It is worse than corruption. And with good reason he makes this charge against them. When the glow of justification is ascribed to another, and a snare is laid for the consciences of men, the Savior no longer occupies his place, and the doctrine of the gospel is utterly ruined.

The gospel of Christ. To know what the leading points of the gospel are is a matter of unceasing importance. When these are attacked, the gospel is destroyed. When he adds the words of Christ, this may be explained in two ways: either that it has come from Christ as its author, or that it purely exhibits Christ. The Apostle’s reason for employing that expression unquestionably was to describe the true and genuine gospel, which alone is worthy of the name.