although I was before a blasphemer, a persecutor, and insolent. However, I obtained mercy, because I did it ignorantly in unbelief.
And a persecutor ... In context this is somewhat of an elaboration upon the preceding word, since it was as "a persecutor" that his speaking against God occurred.  New Testament light on Paul's role as a savage persecutor of the church is given in  Acts 8:3; 9:1 and  Acts 22:19.