All of Grace From Start to Finish
"There is nothing in us or done by us, at any stage of our earthly development, because of which we are acceptable to God. We must always be accepted for Christ’s sake, or we cannot ever be accepted at all. This is not true of us only “when we believe.” It is just as true after we have believed. It will continue to be true as long as we live. Our need of Christ does not cease with our believing; nor does the nature of our relation to Him or to God through Him ever alter, no matter what our attainments in Christian graces or our achievements in Christian behavior may be. It is always on His “blood and righteousness” alone that we can rest. There is never anything that we are or have or do that can take His place, or that can take a place along with Him. We are always unworthy, and all that we have or do of good is always of pure grace."
(The Works of Benjamin B. Warfield, 10 vols. (1991), vol. 7, p. 113; as cited by Steve in a post at The Gate)