Romans 4: 1-5(MSG): So how do we fit what we know of Abraham, our first father in the faith, into this new way of looking at things? If Abraham, by what he did for God, got God to approve him, he could certainly have taken credit for it. But the story we’re given is a God-story, not an Abraham-story. What we read in Scripture is, “Abraham entered into what God was doing for him, and that was the turning point. He trusted God to set him right instead of trying to be right on his own.” If you’re a hard worker and do a good job, you deserve your pay; we don’t call your wages a gift. But if you see that the job is too big for you, that it’s something only God can do, and you trust him to do it—you could never do it for yourself no matter how hard and long you worked—well, that trusting-him-to-do-it is what gets you set right with God, by God. Sheer gift.
Romans 7:18 (NKJV): For I know that in me (that is, in my flesh,) dwelleth no good thing: for to will is present with me; but how to perform that which is good I find not.