Galatians 1

They did not formally deny Christ; they wished to add circumcision. But the gospel which the apostle had preached was the complete and whole gospel. Nothing could be added to it without altering it, without saying that it was not the perfect gospel, without really adding something that was of another nature, that is to say, corrupting it. For the entirely heavenly revelation of God was what Paul had taught them. In his teaching he had completed the circle of the doctrine of God. To add anything to it was to deny its perfection; and to alter its character, to corrupt it. The apostle is not speaking of a doctrine openly opposed to it, but of that which is outside the gospel which he had preached. Thus, he says, there cannot be another gospel; it is a different gospel, but there are no glad tidings except that which he had preached. It is but a corruption of the true, a corruption by which they troubled souls. Thus, in love to souls, he could anathematise those who turned them away from the perfect truth that he had preached. It was the gospel of God Himself. Everything else was of Satan. If Paul himself brought another, let him be anathema. The pure and entire gospel was already proclaimed, and it asserted its claims in the name of God against all that pretended to associate itself with it. Did Paul seek to satisfy the minds of men in his gospel, or to please men? In no wise; he would not thus be the servant of Christ.