1 Corinthians 15:9-10

Amplified Bible, Classic Edition

⁹ For I am the least [worthy] of the apostles, who am not fit or deserving to be called an apostle, because I once wronged and pursued and molested the church of God [oppressing it with cruelty and violence].

¹⁰ But by the grace (the unmerited favor and blessing) of God I am what I am, and His grace toward me was not [found to be] for nothing (fruitless and without effect). In fact, I worked harder than all of them [the apostles], though it was not really I, but the grace (the unmerited favor and blessing) of God which was with me.