What then shall we say was gained by Abraham, our forefather according to the flesh? For if Abraham was justified by works, he has something to boast about, but not before God. For what does the Scripture say? “Abraham believed God, and it was counted to him as righteousness.” Now to the one who works, his wages are not counted as a gift but as his due. And to the one who does not work but believes in him who justifies the ungodly, his faith is counted as righteousness...(Rom. 4:1-5).
What does it mean that Abraham’s faith was counted to him for righteousness apart from works?
Some read this passage and conclude that Paul says a man can do nothing to be reckoned righteous. Is this really what he means? If we understand "works" to mean any work or obedience, then we would certainly have to conclude man can do nothing to be reckoned righteous by God.
First, consider the KIND of works Paul is speaking about: Then what becomes of our boasting? It is excluded. By what kind of law? By a law of works? No, but by the law of faith. For we hold that one is justified by faith apart from works of the law (Rom. 3:27-28)
He is speaking of works of the law, and notice he’s establishing that one is justified by faith not by works of the law. Some Jews had the notion that they could be declared guilt-free, righteous, or justified before God on the basis of law-keeping.
Paul shows that, one, such thinking is utterly wrong because all have sinned and fallen short of the glory of God (v. 23) and, two, Abraham is an example that proves one is justified by faith apart from the works of law.
Paul addresses this again later in Galatians: "For all who rely on works of the law are under a curse; for it is written, 'Cursed be everyone who does not abide by all things written in the Book of the Law, and do them.' Now it is evident that no one is justified before God by the law, for “The righteous shall live by faith” (Gal. 3:10-11).
If one is to be justified by law, he must keep “all things written in it.”
Since a single sin is all that is necessary to establish guilt, and no amount of obedience can remove guilt, once established; it follows that the only way one may be justified (free of guilt) on the basis of law alone is to obey perfectly.
If Abraham was justified by the kind of works under discussion, it would imply that he never sinned––he has something to boast about (v. 2).
Theoretically if one lives perfectly his righteousness would be owed to him by God––like a wage, he would have earned it, but no man can do this!
Abraham's perfect life was NOT the reason he was righteous, for he had no perfect life.
That’s why Paul cites Gen 15:6 to show us how Abraham was justified––his faith was reckoned to him as righteousness.
When Paul says, "If Abraham were justified by works, he has something to boast about..." he is saying Abraham could be proud because he would be justified by perfect law keeping.
Paul continues to clarify in v. 5, notice the one who does not work (the one who can’t claim righteousness on the basis of perfection), but believes in Him (trusts in God to save him––justify him though he had been ungodly)––this is the one God justifies by faith just as he did with Abraham.
Remember the man beating his chest, confessing his sins, crying out for mercy? "This one," Jesus says, "went down to his house justified" (Lk. 18:14).
Paul uses David’s words (forgiven, covered, shall not count sin) to describe righteousness through faith: God extends forgiveness to the humble, faithful individual.
It has nothing to do with his law keeping––circumcision, because God reckoned righteousness to him before he was circumcised. Paul is NOT saying that ANY act of obedience on Abraham's part is incompatible with faith. Just the opposite: God counts all righteous who "walk in the footsteps of the faith that our father Abraham had before he was circumcised" (Rom. 4:12).
Abraham’s faith was reckoned to him as righteousness because he was faithful to God. His righteousness was not of himself, so this implies mercy from God.
This is the point Paul is making — about Abraham, and about children of God today. God forgives those who have proper faith––this makes righteousness a merciful gift from God. What was true for Abraham can be true for us today IF we live by faith.
There is no room for boasting as we strive to live faithful obedient lives. Because a faithful life is still an imperfect life even at its very best, thus we are taught to continually confess our sins, and continually look to the blood of Jesus Christ for forgiveness (1 Jn. 1:9-10).