Paul acknowledges that he doesn’t deserve any of God’s grace because of the things he’s done. And yet God blessed him with supernatural insight into the mystery of Christ, inspiring him to write two thirds of the New Testament and drenched him with so much of the Holy Spirit that his handkerchiefs cast out demons (Acts 19:11-12).
In the movie Man of Steel, Clark discovers his powers and where he’s come from. He never asked for his powers or did anything to deserve them. He has them simply because he’s a Son of Krypton. There’s a scene where his father Jor-El tells him, “You’ve grown stronger here than I ever could’ve imagined. The only way to know how strong, is to keep testing your limits.” In the same way, we never asked for God’s blessings and we certainly didn’t do anything to deserve them, either. But we have them simply because we’re His sons and daughters.
God gave Paul the ministry of preaching the Gospel to the Gentiles and used him to transform the ancient world. He’s given each of us different gifts and ministries as well and wants to use us with just as much earth-shattering power, regardless of how unworthy we feel of it. He’s telling us the same thing Jor-El told Clark–to test the limits of the grace He’s given us. The only difference is that in our case there are no limits to what God has given us and what He can do through us because He’s able to do immeasurably more than all we ask or imagine.