What does Galatians 2:9 mean?
The Christians of Galatia are being influenced by a group known as the Judaizers. These false teachers claim that Gentiles need to be circumcised and to follow Old Testament law in order to be saved. These same men are claiming that Paul's authority is suspect. In response, Paul has pointed out how he obtained his understanding of the gospel directly from Christ, and that he was in total agreement with the other apostles.Paul now makes his strongest point to the Galatian believers: his message of salvation through God's grace without following the Law has been formally approved by the other apostles. Paul met with the other apostles in Jerusalem. The three most influential leaders, James, Peter (Cephas), and John, saw the grace given to Paul by God to carry out his ministry (Galatians 1:15). In other words, they agreed with Paul's testimony that Christ had been revealed to him and had called him as an apostle. So those three gave to Paul and Barnabas, his partner in ministry, their seal of approval called "the right hand of fellowship." We might assume this is a kind of official hand shake, but what "the right hand of fellowship" represents in the New Testament is acceptance and inclusion in the group.
Paul wanted the Galatian Christians to fully understand that he was not some rogue teacher running around the world teaching a maverick version of the gospel. He preached the same message Jesus' closest disciples did. They saw the grace of God in him, and they approved of his ministry. Anyone who would reject the gospel as Paul preached it would also be rejecting the teaching of those most famously connected to Jesus at the time. And, as Paul clarified earlier, this means all who attempt to add additional requirements to salvation, beyond faith in Christ, are false teachers, "false brothers," (Galatians 2:4) and subject to condemnation (Galatians 1:8–9).