The saying is faithful and worthy of all acceptance, that Christ Jesus came into the world to save sinners; of whom I am chief.
(1) His sin was chief in the sense of the zeal and avid delight in which he pursued it.  (2) It was greatest in the diabolical results that would have been achieved if he had continued in it, possibly that of the total destruction of Christianity; surely that was his purpose.  (3) Paul was the chief of sinners because his sin was against Christ himself in the person of his spiritual body on earth.  (4) He was the chief of sinners in the matter of his marvelous abilities, super intellectual powers, unswerving zeal and persistent determination which augmented the threat of his operations against God's purpose on earth in Christ.  (5) He was the foremost among sinners because of the particular historical position which his persecutions held in the very beginning of Christianity.  A million sinners today, operating against Christianity with Pauline zeal and power, would not pose a fraction of the threat inherent in the activities of Paul at that singular period in history.