I want to preface this by saying I don't believe Paul was a false Apostle. I must either view his Apostleship as authentic, or throw away everything I believe. Removing Paul's writings and influence from the New Testament would change the message completely.
The reason I ask is that every so often, I have doubts about whether Paul was authentic, or an insidious infiltrator. Usually, when this happens, I pray about it and ask God to forgive whichever sin I'm guilty of - my unbelief in His word (which I'd be guilty of if Paul is authentic, and I'm doubting it), or being deceived by Paul (What a horrible thought), and tell Him that I put my trust in Him.
When I have these doubts, they arise from several thoughts.
First, Saul (his name before his conversion for those few that don't know) hated Christianity. He had been doing his best (or worst) to eliminate it. He wasn't having much success with direct opposition. Maybe he thought that if he got to be an insider with influence, he could corrupt the teachings from the inside? (He wouldn't be the first or the last.)
Next, nobody witnessed his conversion. He was on the road alone, and we have only his word for it.
Third, his teachings on salvation apart from works seems to contradict other clear teachings.
Before posting this question, I did a quick Google search, and I did run across some who hold this position and make arguments for it. Here's one. The arguments are, at the very least, well-reasoned.
Again, I don't hold the position that he is a false Apostle, but if he is, then it has serious implications for my own beliefs, and for the validity of mainstream Christianity. I understand just how "heretical" and "blasphemous" it must seem to even ask such a question, and just how deep the implications of what I'm asking go. I'm hoping to find answers from others who have studied this out, or who have at least heard the arguments for and against such a view.