Chrysostom on Righteousness
And he well said, “a righteousness of mine own,” not that which I gained by labor and toil, but that which I found from grace. If then he who was so excellent is saved by grace, much more are you. For since it was likely they would say that the righteousness which comes from toil is the greater, he shows that it is dung in comparison with the other. For otherwise I, who was so excellent in it, would not have cast it away, and run to the other. But what is that other? That which is from the faith of God, i.e. it too is given by God. This is the righteousness of God; this is altogether a gift. And the gifts of God far exceed those worthless good deeds, which are due to our own diligence.
–Chrysostom, Homily on Philippians 3
With thanks to W.W. for the quote.