It holds up the broken chair. It gives the upper-body strength. It prevents other obstacles. It keeps his heart beating. It keeps his eyes seeing.
Grace sustains everything in the Christian life.
Let me show you a few verses to give some Biblical basis to this claim. But in spite of this there was boasting going on in the church at Corinth. Which to Paul's mind was totally contradictory to reality. Grace eliminates boasting. You can't boast as though you create and sustain what grace creates and sustains.