What does it mean in Romans 4:2 that if Abraham was justified by works he would have something to boast about?
It means if Abraham was justified by his own accomplishments or what he earned, he would have grounds to glory or brag. Yet that boasting could never be before God; no one can brag to God, and God would not allow even Abraham to claim credit for his patience or works.
Les explains that Romans 4:2 asks whether Abraham was justified by works, meaning by what he could accomplish or earn. If that were true, Abraham would have reason to glory or brag, but never before God. No one will ever brag to God, "look what I've done," and God will never have it. Even with a man like Abraham, God would not allow him to come to the place where he could brag about being patient and waiting for the promises. In fact, while Abraham was waiting, he failed miserably and fell flat on his face. Earlier, Les also notes that God does not use gifted, wealthy, intelligent human beings because they would be too apt to brag, and that even Abraham's justification was faith plus nothing, not something he had accomplished.
For if Abraham were justified by works, he hath whereof to glory; but not before God.
More Questions
If Abraham were justified by works, would he have been able to glory and boast?
If Abraham had been justified by works, he would have had grounds to glory and would naturally have become proud, able to tell people, 'look what I have done to inherit eternal life.'
If Abraham could be justified by works, what would he have been able to glory about?
If Abraham had been justified by works, he would have had ground to glory; he would have become proud and could boast about what he had done to inherit eternal life.