1 Corinthians 15:9

For I am the meanest of the Apostles, I who am unworthy of the name of 'Apostle,' because I persecuted the Church of God.

Acts 8:3

But Saul began to devastate the Church; he entered house after house, dragged out men and women alike, and threw them into prison.

2 Corinthians 12:11

I have been "playing the fool!" It is you who drove me to it. For it is you who ought to have been commending me! Although I am nobody, in no respect did I prove inferior to the most eminent Apostles.

Ephesians 3:7-8

Of this Good News I became a minister, in virtue of the charge with which God entrusted me in the exercise of his power--

1 Timothy 1:13-15

though I once used to blaspheme, and to persecute, and to insult. Yet mercy was shown me, because I acted in ignorance, while still an unbeliever;

Acts 9:1-19

Meanwhile Saul, still breathing murderous threats against the disciples of the Lord, went to the High Priest,

Acts 22:4-5

In my persecution of this Cause I did not stop even at the taking of life. I put in chains, and imprisoned, men and women alike--

Acts 26:9-11

I myself, it is true, once thought it my duty to oppose in every way the Name of Jesus of Nazareth;

2 Corinthians 11:5

I do not regard myself as in any way inferior to the most eminent Apostles!

Galatians 1:13

You heard, no doubt, of my conduct when I was devoted to Judaism--how I persecuted the Church of God to an extent beyond belief, and made havoc of it,

Galatians 1:23

All that they had heard was--'The man who once persecuted us is now telling the Good News of the very Faith of which he once made havoc.'

Philippians 3:6

As to zeal, I was a persecutor of the Church; as to such righteousness as is due to Law, I proved myself blameless.

Treasury of Scripture Knowledge

Summary

For I am the least of the apostles, that am not meet to be called an apostle, because I persecuted the church of God.

General references

Bible References

Because

Acts 8:3
But Saul began to devastate the Church; he entered house after house, dragged out men and women alike, and threw them into prison.
Acts 9:1
Meanwhile Saul, still breathing murderous threats against the disciples of the Lord, went to the High Priest,
Acts 22:4
In my persecution of this Cause I did not stop even at the taking of life. I put in chains, and imprisoned, men and women alike--
Acts 26:9
I myself, it is true, once thought it my duty to oppose in every way the Name of Jesus of Nazareth;
Galatians 1:13
You heard, no doubt, of my conduct when I was devoted to Judaism--how I persecuted the Church of God to an extent beyond belief, and made havoc of it,
Philippians 3:6
As to zeal, I was a persecutor of the Church; as to such righteousness as is due to Law, I proved myself blameless.
1 Timothy 1:13
though I once used to blaspheme, and to persecute, and to insult. Yet mercy was shown me, because I acted in ignorance, while still an unbeliever;

General references

Luke 17:10
And so with you--when you have done all that you have been told, still say 'We are but useless servants; we have done no more than we ought to have done.'"
Acts 8:3
But Saul began to devastate the Church; he entered house after house, dragged out men and women alike, and threw them into prison.