Galatians 2:3

The apostles in Jerusalem fully agreed with Paul's message. They all believed the same good news: God's grace comes through faith in Christ, not by following the law. The Jerusalem apostles clearly did not believe that circumcision was necessary for a non-Jew like Titus.

When Paul visited Jerusalem for the second time, the other apostles agreed that what he was teaching was correct. According to tradition, Paul was writing about the important meeting of church leaders described in Acts 15:1–41. However, it is more likely that Paul was talking about his earlier visit to Jerusalem (Acts 11:30; 12:25; see Galatians Book Introduction, "Date of Writing").

The Judaizers (people who insisted on following Jewish customs) came to Galatia. They preached that both faith and circumcision were necessary. They questioned Paul's authority as an apostle and tried to discredit his message. Paul defended his authority by showing that past events proved his message was the true good news.

Some people were against Paul and questioned whether he was a true apostle. They did not believe he was honest and did not think he had the right to be a leader in the church. So Paul begins his letter by explaining that he really was an apostle with authority from God.