What does Galatians 2:8 mean?
Paul is writing to Christians in the region of Galatia who happily believed in Jesus and became Christians when he came to them. Later, though, a group called the Judaizers came and insisted that Paul was wrong. This sect said these Gentiles must be circumcised and follow the law of Moses to be truly saved. Paul's stance on this view is clear: these Judaizers are not even Christians themselves, and that the other apostles agree with him. When a person tries to add any other requirement to salvation, they are preaching something false.Peter and the others have recognized that he, Paul, has been sent by Christ to preach the true gospel message to Gentiles, just as Peter's mission is to take the good news of Jesus to Jewish people, referred to as "the circumcised".
Now Paul points to something essential: The same Jesus is working through Paul in his ministry and working through Peter in his ministry. The only difference is the audience. It's the same Jesus, same message, and same way to be saved—through the grace of God and not human effort.