Departure from the gospel by reverting back to the ceremonies of the Mosaic law.
Paul defends the truth and authority of the Gospel being above the Apostles (e.g., Peter).
Gal. 2:6-10 The same gospel is for the Jews and Gentiles
The universality of the same gospel of grace given to both Jews and Gentiles affirmed by the Apostles.
The proclamation of the gospel by a true apostle of the Lord Jesus Christ: Paul.