according to the Gospel of the glory of the blessed God, which was committed to my trust.

 That is what Paul was once like in regard to the Christian Church. Not content with words of insult, he went to the limit of legal persecution. Not content with legal persecution, he went to the limit of sadistic brutality in his attempt to stamp out the Christian faith. He remembered that; and to the end of the day he regarded himself as the chief of sinners. It is not that he was the chief of sinners; he still is. True, he could never forget that he was a forgiven sinner; but neither could he ever forget that he was a sinner. Why should he remember his sin with such vividness? 