VERSE 7. And would pervert the gospel of Christ. To paraphrase this sentence: "These false apostles do not merely trouble you, they abolish Christ's Gospel. They act as if they were the only true Gospel-preachers. For all that they muddle Law and Gospel. As a result they pervert the Gospel. Either Christ must live and the Law perish, or the Law remains and Christ must perish; Christ and the Law cannot dwell side by side in the conscience. It is either grace or law. To muddle the two is to eliminate the Gospel of Christ entirely." It seems a small matter to mingle the Law and Gospel, faith and works, but it creates more mischief than man's brain can conceive. To mix Law and Gospel not only clouds the knowledge of grace, it cuts out Christ altogether. The words of Paul, "and would pervert the gospel of Christ," also indicate how arrogant these false apostles were. They were shameless boasters. Paul simply had to exalt his own ministry and Gospel.
Luther, Martin; Graebner, Theodore (2011-03-24). Commentary on the Epistle to the Galatians (Kindle Locations 329-335). Kindle Edition.
We now hear what kind of doctrine was committed to Paul: The doctrine of the Gospel, the doctrine of the revelation of the Son of God. This doctrine differs greatly from the Law. The Law terrorizes the conscience. The Law reveals the wrath and judgment of God. The Gospel does not threaten. The Gospel announces that Christ is come to forgive the sins of the world. The Gospel conveys to us the inestimable treasures of God.
Luther, Martin; Graebner, Theodore (2011-03-24). Commentary on the Epistle to the Galatians (Kindle Locations 463-466). Kindle Edition.