When Paul speaks in great detail about Abraham’s faith in Romans 4:1–25, he does not abandon the theme of the law.
After all, this patriarch was in the law
for it is through the Torah that we came to know Abraham as the father of the nation to whom the law of Moses was given. It is significant, however, that he also predated the law. Abraham lived before Moses appeared on the scene, and Abraham’s appearance at the very beginning of the Hebrew Bible affirms that faith in no way nullifies the law (Romans 3:31). In fact, the Hebrew Bible itself demonstrates how faith excludes all forms of boasting. Abraham serves as a pre-eminent example of the law of faith that Paul had just discussed.
To Gentile Christians in Rome it may have seemed as though they have no connection to the patriarch Abraham. After all, they do not live under the law like Jews. Does this not mean that they therefore fall outside the of Abraham’s circle and are excluded from the promises that God once made to this patriarch? In their specific context in the city of Rome, the question actually arose whether the new Christian Church, which operated separately from the synagogue, would not remain separated from the God of Abraham, Isaac, and Jacob. To support the members of the church in their debates with the Jews, Paul provides them with valuable material concerning the patriarch Abraham, with whom it all began (see also Lincoln’s Abraham Goes to Rome
1).
Because the inclusion of the Gentiles in the covenant is such an important point, Paul develops this idea further in Romans 4:13–25. The second-half of Romans 4:1–25 therefore does not offer anything new, but elaborates upon the idea that faith precedes the law. It is striking that here, just as in Romans 1:1–32, the end of faith lies in giving glory to God (Romans 4:20b).
In Romans 4:1–25 Paul thoroughly debunks the objection that a justifying faith in Jesus is unthinkable apart from the law, for this faith is older than the law. It as old as Father Abraham. The Christians in Rome, the majority of whom originated from the Gentiles, were thereby equipped to counter the non-Christian Jews, to parry their attacks, and to invite them to persevere in the faith of Abraham by coming to accept Jesus as the Messiah.2
1 What then shall we say was gained by Abraham, our forefather according to the flesh?