As for zeal, persecuting the church; as for righteousness based on the law, faultless.
NIV
As to my zeal, I was a persecutor of the church, and by the Law's standard of righteousness (supposed justice, uprightness, and right standing with God) I was proven to be blameless and no fault was found with me.
AMP
Concerning zeal, persecuting the church; touching the righteousness which is in the law, blameless.
KJV
"Who are you, Lord?" Saul asked. "I am Jesus, whom you are persecuting," he replied.
NIV
And Saul said, Who are You, Lord? And He said, I am Jesus, Whom you are persecuting. It is dangerous and it will turn out badly for you to keep kicking against the goad [to offer vain and perilous resistance].
AMP
And he said, Who art thou, Lord? And the Lord said, I am Jesus whom thou persecutest: it is hard for thee to kick against the pricks.
KJV
Many a time I went from one synagogue to another to have them punished, and I tried to force them to blaspheme. I was so obsessed with persecuting them that I even hunted them down in foreign cities.
NIV
And frequently I punished them in all the synagogues to make them blaspheme; and in my bitter fury against them, I harassed (troubled, molested, persecuted) and pursued them even to foreign cities.
AMP
And I punished them oft in every synagogue, and compelled them to blaspheme; and being exceedingly mad against them, I persecuted them even unto strange cities.
KJV