Something from St. Augustine, Bishop of Hippo (November 13, 354 - August 28, 430) on Good Works and Grace, noting that any good work we do is God working through us so that God rewards his own grace. All of our salvation is God's doing, even our good works.
“It is His own gifts that God crowns, not your merits—if, at least, your merits are of your own self, not of Him. If, indeed, they are such, they are evil; and God does not crown them; but if they are good, they are God's gifts. ….
“If, then, your good merits are God's gifts, God does not crown your merits as your merits, but as His own gifts.” (Augustine, Selections from “On Grace and Free Will,” chapter 15)