No Other Gospel

Galatians 1
6I am astonished that you are so quickly deserting the one who called you by the grace of Christ and are turning to a different gospel— 7which is really no gospel at all. Evidently some people are throwing you into confusion and are trying to pervert the gospel of Christ. 8But even if we or an angel from heaven should preach a gospel other than the one we preached to you, let him be eternally condemned! 9As we have already said, so now I say again: If anybody is preaching to you a gospel other than what you accepted, let him be eternally condemned!
10Am I now trying to win the approval of men, or of God? Or am I trying to please men? If I were still trying to please men, I would not be a servant of Christ.