Michael Kruger nails it at The Gospel Coalition:
When it comes to our justification — our legal standing before God — our own good works are in no way the grounds of God’s declaration that we are “righteous.” Indeed, the gospel is good news because we are saved not by what we have done, but by what Christ has done. We are accepted by God not because of our works, but in spite of them.
So what does God think of our good works after we are saved? Here, unfortunately, Christians often receive mixed messages. Somewhere along the way we have begun to believe that our pride is best held in check, and God’s grace is most magnified, when we denigrate all our efforts and all our labors as merely “filthy rags” in the sight of God (Is. 64:6).
But does God really view the Spirit-wrought works of his own children in such a fashion? Is God pleased only with Christ’s work, and always displeased with our own?