1 Corinthians 15:9-11

For I am the least of the apostles and do not even deserve 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 to me was not without effect. No, I worked harder than all of them—yet not I, but the grace of God that was with me. Whether, then, it is I or they, this is what we preach, and this is what you believed.