11 I want you to know, brothers and sisters, that the gospel I preached is not of human origin. 12 I did not receive it from any human source, nor was I taught it; rather, I received it by revelation from Jesus Christ. (TNIV)These two verses are the main thesis that Paul argues from here through the end of chapter 2. The Teachers claimed that Paul had been taught the gospel by the apostles in Jerusalem and that he was guilty of abbreviating the gospel that he had received by either (depending on how you come down on the New Perspective on Paul – an issue we’ll address later in Galatians) not requiring the Gentiles to follow the Mosaic Law or not requiring Gentiles to become like ethnic Jews by not forcing them to be circumcised and follow sabbath and food laws. Luther grasped the force of the Teachers arguments well:
They were saying that Paul was inferior to the rest of the apostles’ followers, who had received what they taught from the apostles; they had also observed their behavior for a long time, and Paul had received the same things from them, they claimed…Why then would the Galatians choose to obey an inferior authority and despise that of the apostles themselves, who were the prime elders and teachers not only of the Galatians but also of all the churches throughout the whole world? (Luther p. 57).Many would have found such a claim to be very persuasive. However, it was not the truth. Paul contradicts the Teachers, stating that what he received was a revelation of Jesus Christ.  It did not come via any human agency. The crucified and risen Christ himself was revealed to Paul on the Damascus road. That was the source of Paul’s knowledge of the gospel. In the following sections Paul will develop this thought more.
 Pace the TNIV and following Hays (p. 211) I take the genitive ‘of Jesus Christ’ as an objective genitive on the basis of vs. 16.