George Leo Haydock

Because I did it ignorantly in unbelief, or in incredulity. Not that we can think it an invincible and altogether an inculpable ignorance, such as would have made St. Paul blameless in the sight of God. It was through his pure mercy that he called St. Paul, when his great sins and false zeal made him a greater object of the divine mercy: and God in him was pleased to make known to all men his wonderful patience, that no sinner might despair. The grace of God was superabounding, or exceedingly abundant in him. (Witham)