Paul was a Pharisee and quite successful. He was in a position where he could very easily say, "I am what I am by the power of my hand to produce the obvious results seen in my own life. Look! As touching the Law I am blameless, it's no wonder my name is Saul, which means big." But by the grace of God, Saul became Paul. Paul, which means little, began to decrease as Jesus increased with each revelation of grace.
The Holy Spirit so often reveals our utter destitution to reveal our perfect strength and sufficiency in grace. Think about Adam, a sinner and covered with false coverings, now covered by the skins of animals (speaking of his salvation by grace). He could not say, "I am what I am by the grace of God; I am a sinner, but I am a saint." Abraham, you are the Father of our faith, you must have been quite special in your performance. And you Jacob, you also, having now the title as the Father of all Israel, must have been extremely special in your performance. What do you have to say?
"We are what we are by the grace of God."
Imagine, all the heavenly witnesses bowing down personally before Jesus and saying with such clarity-"I am what You've made me to be by the grace of God." The thief on the cross will be there also. This man was never baptized, never attended a church service, never heard a sermon, and never won a soul to Christ, but he has made it because of grace.