Hey, he asked! His question was if you removed all the NT teachings from St. Paul what would we have left for doctrine?
Protestants seem to think that without St. Paul, Christianity would have been in some kind of vacuum and would be without any merit/doctrine
It seems that they forget that before St. Paul, DOCTRINE had already BEEN SET by Jesus Christ and He commissioned His Twelve Apostles to go for forward and spread the good news.
In the second chapter of the Book of Acts, St. Peter stood up during Pentecost, gave a small sermon, and the Church added about 3,000 souls that day. At the end of the second chapter it also states that they were adding to the Church daily.
This was before St. Paul came onto the scene. Do you think they converted thousands of people to the Church without having doctrine/doctrines set in place?
But don't forget that the Gospel that Paul preached came from the Resurrected and Ascended Jesus Christ. He received it directly and personally on the road to Damascus and he spent many years with the Lord before he began his ministry.