Paul wants to establish his apostleship at the beginning of Galatians, because his authority has been attacked by false teachers. They are preaching a false gospel and part of their strategy was to undermine the true gospel by assailing its messenger. In the very first verse of Galatians Paul wants to establish the divine quality of the epistle, and he writes: “Paul, an apostle, (not of men, neither by man, but by Jesus Christ, and God the Father, who raised him from the dead;)” They were saying his apostleship was only human, nothing from God. Paul says it was “not of men,” in an emphatic repetition, “neither by man,” and then the contrasting, “but by Jesus Christ.” Paul makes a strong statement of the deity of Christ by contrasting Jesus from men as divine – not of men, but by Jesus Christ. If Paul was an apostle not of men, but of Jesus Christ, He is with great emphasis saying that Jesus is God. It doesn’t make any sense otherwise.