Galatians 1:10-12 (ESV)
For am I now seeking the approval of man, or of God? Or am I trying to please man? If I were still trying to please man, I would not be a servant of Christ.
 For I would have you know, brothers, that the gospel that was preached by me is not man's gospel.  For I did not receive it from any man, nor was I taught it, but I received it through a revelation of Jesus Christ.
This is the claim that Paul makes. The Gospel I preach was received from Christ. This is not something you can pick at. It is not a self serve buffet. If you take it you take all of it. If you don’t take part of it, you leave all of it on the table. Either it came from Christ or it did not. Paul says it came through a revelation of Jesus Christ. I wonder how many of those he received, evidently more than the one recorded in acts where he fell off a donkey. Paul is adamant; it is not man’s gospel. That makes sense if it were a man’s gospel I would expect it to be quite a bit different. If my old Adam were to come up with a religion it would be quite different than the free forgiveness of sins. It would be a lot more appealing to the world. I don’t have an ascetic bent in me, so it probably wouldn’t go that way. It would probably be a self serving religion of excess. It would probably revolve around me in any case. Notice Paul doesn’t preach himself. When he does talk about himself, he exposes himself as a sinner. He preaches Christ.