One of Paul’s aims in his argument is to exclude human boasting. Our only boast is the Gospel, he has previously expressed this point in the under-stated form, “I am not ashamed of the Gospel.”[1] Boasting is excluded by a form of Law. Paul distinguishes between a Law of Works, what you do or a law of faith, what you believe, and he argues that it is the latter that excludes boasting (v27). This is because of the point he has already made, that justification is through the law of faith not works (v28).
The reason for this is to vindicate God as the true God of all people, Jews and Gentiles alike, not just the Jews. This means he must deal with both in the same way, by faith (v29-30). Does this mean that the Law is redundant, usurped? “By no means”, concludes the apostle.
[1] Romans 1:16.
Faithroots 