Having highlighted the key issue that prompted his letter (Galatians 1:6–10), Paul will go on to give support for his assertion that the gospel, which he proclaimed, is trustworthy and authentic. He will testify as to how he received that gospel (Galatians 1:12), and the transformation that took place in his life (Galatians 1:13–17). Thereafter, Paul makes it clear that he spent a long time proclaiming that gospel, without any contact with another apostle (Galatians 1:18–24).
In order to defend the truth and authority of the gospel, Paul gives lots of autobiographical details.1 He does not share everything that happened with him since his conversion, only those details that support his argument regarding the divine origin of his gospel message.2 His argument implies that the Judaizers were teaching the Galatians that Paul learned his gospel from the apostles and elders in Jerusalem (and then distorted what they taught).3
Galatians 1:1 – 2:21 can be further subdivided as follows:4
Greeting: Paul’s apostolic authority (Galatians 1:1–5)
Problem explained: Desertion from the gospel (Galatians 1:6–10)
Paul’s gospel derived from God, not from people (Galatians 1:11 – 2:21)
11 For I would have you know, brothers, that the gospel that was preached by me is not man’s gospel.