1 What then shall we say that Abraham our father has found according to the flesh? 2 For if Abraham was justified by works, he has something to boast about, but not before God.
Chapter four presents illustrations of justification by faith rather than by works. This furthers the argument of Romans 3:21-31. Paul cites Abraham and David as Old Testament figures justified by faith. The thesis is that justification by faith was no new novelty in Scripture.
4:1
What then [therefore—draws inference from chapter three] shall we say
What is the lesson we learn from the experience of Abraham, who lived about 2,000 years before Paul, regarding justification by faith apart from works?
that Abraham our father has found [discovered grace] according to the flesh [from human capacity]?
The phrase “Abraham our father” refers to Paul’s identity with the Jewish people. Abraham was the most influential figure in Judaism. Paul made a distinction between Abraham’s physical ancestry and his spiritual fatherhood. Paul was a Jew and had a physical kinship with Abraham. What lesson did the first physical Jew learn about justification by faith?
The Greek tense (perfect) of the word “has found” indicates Abraham’s finding grace as lasting.
4:2
For if Abraham was justified by works,
If we assume that it is true that Abraham was justified by “works,” what is the result of that hypothesis?
he has something to boast about,
It is true that if, and that is a big “if,” works justified Abraham, then he can brag about what he did. Boasting would be legitimate in that case if salvation were by works.
but not before [in God’s presence] God.
The word “but” is a right-about-face word. Abraham could boast before people but not before God. Finite righteousness is not sufficient for attaining infinite or absolute righteousness. Salvation comes by faith in God, not by work for God. Salvation is by faith alone. If God did not justify Abraham by works, who can be?
Abraham had no claim on God whatsoever; therefore, he would be in a state of separation from God if he depended on his works. A person who is less perfect than God is a sinner. If that were true with Abraham, it would mean that all men are bankrupt and hopeless before God. Yet, it was in this bankrupt condition of Abraham that God offered him salvation by simple faith. This kind of salvation is unadulterated grace.
PRINCIPLE:
Self-applause is an indication of being out of phase with God.
APPLICATION:
Man needs to be careful with self-applause before God, especially since God views him as spiritually bankrupt. When we recognize our spiritual bankruptcy before God, He will offer us His grace.
It is very important not to confuse Romans 4:3 with James 2:21. The difference between these two Scriptures is in who is doing the justifying. In Romans, it is God who justifies. In James, it is people who justify or vindicate the believer’s walk before God.

It seems that in the Old Testament faith was an action word. It also seems that “that action” was for the benefit of people to see(read) what faith looked like. God already knew Abrahams’ heart of faith. That is in comparison to the verses in James.