1 Corinthians 15:9-11 New International Version (NIV)

9 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. 10 But by the grace of God I am what I am, and his grace to mewas not without effect. No, I worked harder than all of them—yet not I, but the grace of God that was with me. 11 Whether, then, it is I or they, this is what we preach, and this is what you believed.