The flesh profits nothing, it is the Spirit that gives life. For there is no work, no deed, nor anything else that God would regard as righteous, but only such as those that come from Himself. For, there is none that is righteous, that is, in their flesh in themselves, that could ever perform any good thing, for all have turned aside and gone after their own way.
What righteousness could we do? We can hear, we can obey, and we can follow. Those good works that God has prepared in advance for us to do, we do, and because it is by faith, God counts it as righteousness.
They are pure works, so long as they are in, by, and only of Him. Though they are performed by our hands, they are His deeds, and therefore, so long as they are fully surrendered to Him, those parts of the deeds are flawless.