This doesn't make sense because Paul lived with most of the other apostles and direct disciples of Jesus. There was a community in which everyone was very close; if he preached something contrary to what Jesus taught, he would have been unmasked from the beginning; note: The oldest texts in the Bible are written by Paul himself, some apostles who knew Jesus in life only wrote their gospels years later.
RE: "All have sinned," says Paul, so what about the Immaculate Conception of Mary?