Some people would dearly love to drive a wedge between Paul’s message and that of Jesus, or between Paul’s teaching and the rest of the New Testament. And this is nothing new…
The false teachers in Galatia had been trying to discredit not only Paul himself (by making out that he was not a ‘proper’ apostle) but also his message. So he begins his letter with an extended defence of both his calling and his preaching. To judge from his vehement rebuttals, he was accused of preaching a message of his own invention (Galatians 1:11,12) without authority from the apostles in Jerusalem (Galatians 2:2,3), and of compromising on the Law in order to attract Gentiles into the church (Galatians 1:10).
In his defence, Paul reminded his readers of his original apostolic commission, received directly from Jesus himself at the time of his conversion. There were many ‘ordinary’ apostles (men and women sent on missions by churches); but Paul was one of the select few who had been commissioned in person by the risen Christ and authorised to teach in His name (Galatians 1:1). And his gospel was the genuine article! He did not make it up himself, nor was it obtained ‘second-hand’ from someone else; like the other apostles, he received it by direct revelation from Christ Himself. “I am sending you… to open their eyes and turn them from darkness to light, and from the power of Satan to God, so that they may receive forgiveness of sins and a place among those who are sanctified by faith in Me.” (Acts 26:17,18)
Paul had initially withdrawn from both Jewish and Christian society for a prolonged period of reflection and meditation. He then began his preaching career in Damascus (Galatians 1:17,18); only after several years of independent work did he consult with the church leaders in Jerusalem. But when he did so, they had no objections or complaints about what he was preaching. On the contrary, they endorsed his message and gave his Gentile mission their full backing (Galatians 2:6-10). The inclusion of Titus in the delegation had been potentially provocative, but the fact that this uncircumcised Gentile had been accepted as a Christian brother (Galatians 2:3) was strong evidence in support of Paul’s case, and undermined the Judaisers’ claim that they were acting under apostolic authority.