I Corinthians 15:9-11

For I am the least of the apostles, who am not worthy to be called an apostle, because I persecuted the church of God. But by the grace of God I am what I am, and His grace toward me was not in vain; but I labored more abundantly than they all, yet not I, but the grace of God which was with me. Therefore, whether it was I or they, so we preach and so you believed.