Note 3 at Acts 22:4: Prior to this the scriptures revealed that Paul had persecuted the Christians (Acts 8:1, 3; 9:1-2) but it had not been mentioned that he had actually killed any believers. Paul must be referring to the time when he consented to Stephen's death (Acts 8:1) or either Paul is giving us additional insight into just how far he went in his persecution of the disciples of Jesus. He did clearly state that Christians were put to death with his approval (Acts 26:10).