I also think we discount the notion of grace. Some think grace only has to do with God's forgiveness of our sins that ultimately lets us in heaven despite our imperfection.
Yet God tells us repeatedly we are to be holy and obedient while in this life. Problem: we all sin, we all fall short of God's glory. We are still expected to strive, to do our best to emulate Christ, and Christ rewards our eforts with His grace. His grace makes up what we lack and helps us be holy.
Of course we can't do everything by ourselves. But that doesn't mean that we shouldn't do ANYTHING. We do what we can, and Crist lifts us up and helps us along. Why else would we have the gifts of the spirit?
"For we are His workmanship, created in Christ Jesus for good works, which God prepared beforehand that we should walk in them."
What does Paul mean?
Look at 1 Corinthians 9:24, "Do you not know that those who run in a race all run, but one receives the prize? Run in such a way that you may obtain it."
What does Paul mean?
We really don't do anything by ourselves, we only do what we should be doing when we are obedient, and to live a life of integrity brings reward.