Who was before a blasphemer, and a persecutor, and injurious: but I obtained mercy, because I did it ignorantly in unbelief. A blasphemer - Speaking impiously and unjustly of Jesus, his doctrine, his ways, and his followers.
And - persecutor - Endeavouring, to the uttermost of his power, to exterminate all who called on the name of the Lord Jesus.
And injurious - Και ὑβριστην· As full of insolence as I was of malevolence; and yet, all the while, thinking I did God service, while sacrificing men and women to my own prejudices and intolerance.
I did it ignorantly in unbelief - Not having considered the nature and evidences of Christianity, and not having believed that Jesus was the promised Messiah, I acted wholly under the prejudices that influenced my countrymen in general. God therefore showed me mercy, because I acted under this influence, not knowing better. This extension of mercy, does not, however, excuse the infuriated conduct of Saul of Tarsus, for he says himself that he was exceedingly mad against them. Let us beware, lest we lose the man's former crimes in his after character.