Sincerely Wrong Paul is a classic example first of a religious man, then later on of a man who came into possession of true spiritual knowledge. He recounts his religious qualifications in Phil. It is an impressive list and shows the degree to which he excelled in the religion of the Pharisees. No one could deny that he was very zealous and sincere. He himself wrote in Rom.
Sincerity is good but it is no guarantee of spiritual success.
Suppose a man is traveling along a road that leads to New York. But suppose also that his sincere belief and intention is to go to Chicago. All the sincerity in the world will not alter his destination. If his ignorance and error are not corrected he will most surely arrive in New York if he continues his present course. This is a picture of most religion.