A NPP exegesis of Romans 4:4-5
A central part of the New Perspective on Paul has been the recognition that when Paul speaks of the "works of the Law" he does not mean moral good works, but rather the following of Jewish customs such as circumcision, dietary rules, sabbath keeping and so forth, which Paul calls "works of the Law". Paul's belief was that a person did not need to adopt Jewish customs to be acceptable to God, but rather that God accepted both Jews and Gentiles who were faithful to him, who were living morally in accordance with his will. This distinction is needed, for example, to explain Paul's arguments in Galatians where Paul spends four chapters attacking the value works of the law and then turns around and spends the last two chapters affirming the saving value of works of morality.
Paul, sadly, does not meet 21st century standards of using perfectly clear and unambiguous terms in 100% consistent ways. So it requires some level of attention on the part of the reader to determine from the context of his argument when he is talking about morality and when he is talking about Jewish customs, as the words "works" and "law" sometimes occur in the context of each. Romans is certainly no exception to this, as Paul in Romans 2 affirms that God will judge people "according to their works" (of morality) and that it is the "doers of the law who are justified" (ie the moral law) but by 3:28 is asserting that "works of the law" (Jewish customs) are not the criterion of God's judgment. In the second half of chapter 3 and the first half of chapter 4, Paul engages in a somewhat convoluted argument against this idea of Jewishness as achieving righteousness before God.
In 3:9-26 Paul has argued that there is no distinction between followers of Jewish customs and followers of Greek customs before God: Anyone who is faithfully obedient to God's moral commands is acceptable. Paul asks about what happens to "boasting" (3:27). If the Jews are they elect of God then they can claim to have been honoured above the Gentiles, but if God honours anyone who is faithful then the Jews don't have any privileged status to boast about (3:27-28). Paul clarifies that this would be analogous to God being "the God of the Jews only" and argues that God is not the God of the Jews only and will justify both those who follow Jewish customs and those who follow Greek ones (3:29-30).
Paul then turns to Abraham in chapter 4 and argues that when Abraham was called righteous by God it was at a time when Abraham was not a follower of Jewish customs and his righteousness was due to his faithfulness. Paul observes that if Abraham had been chosen arbitrarily by God because of Jewishness then he could have claimed to have been honoured above Gentiles by God (4:2), but he could not have claimed honour in God's sight because God would have been arbitrarily gifting him honour. (Paul's comment about Abraham not being able to claim honour from God would make no sense if he was talking about moral good works) Paul reiterates that Abraham's righteousness came from his "faithfulness" (4:3). Then follows 4:4-5, to which I will return shortly.
Paul says David teaches that people can be righteous apart from Jewish customs, arguing that God's forgiveness and acceptance is available to both those who are circumcised and those who are not (4:6-9a). Paul argues that Abraham did not follow Jewish customs when God first called him righteous (4:9b-11a). God calling him righteous was because of his faithfulness not his Jewishness. He argues that like Abraham, those who now have faithfulness but do not follow Jewish customs are righteous (4:11b-17). Paul argues that God's promise to Abraham that his descendants would inherit the world would not be true if Abraham's descendants were limited to those who followed Jewish customs. Rather Abraham's true descendants are peoples of all nations who share the faithfulness that he exemplified.
Paul in the course of this argument has created a distinction between two groups of ideas. In one group are "Jewish Customs", "Law", and "works". In the other group are "faithfulness" and "justification". The average Jew of Paul's time would have argued these two groups of ideas are identical, saying that a person's faithfulness to God is demonstrated by their performance of God's commands - and that faithfulness to God and following the Jewish customs laid out by the law are therefore interchangeable. Paul however, is trying to make these two groups of ideas stand in a contrast throughout his argument. As a rhetorical ploy, in 4:4 he employs an analogy from everyday life in the ancient world that contrasts these two groups of ideas.
In 4:4 he gives this analogy which draws on two contrasting economic systems that ran side-by-side in Paul's day relating to work and payment. One was an informal system in which favours were exchanged as gifts and faithfulness was key. The other was a formal legal system in which work was performed contractually and a legal obligation for repayment existed. It is these systems which provide the separation Paul is looking for between his two categories. This contrasts faithfulness, favour, non-law, and non-work against law, and work. This provides the contrast that Paul is looking for between his two groups of ideas. Thus in 4:4 he references briefly the everyday-reality of these dual systems, which his Roman readers understood well (but which can seem strange to us today).
In 4:5 Paul draws this contrast into his argument, restating again his thesis that the person who does not follow Jewish customs but who is faithful to God is righteous. In this sentence, Paul speaks of God as being the God who justifies the "ungodly". This seems to be a somewhat derogatory Jewish term to refer to those who did not follow Jewish customs. Paul elsewhere speaks of "Gentile sinners" in the same vein. For Paul, God is a God who will call righteous these 'ungodly' Gentiles that do not keep the Jewish customs because they are faithful to God and keep God's moral law. He is the God of the Gentiles and not just the God of the Jews.
Romans 4:4-5 in my view, is thus a small part of Paul's wider argument advocating that what matters to God is a person's moral behavior and not their cultural customs. It is a brief reference to the everyday practices of the Roman world, and this reference is lost on many today. By failing to perceive this reference, and by misconstruing Paul's use of the word "works" in this argument, and by taking the passage out of the context of Paul's wider argument, the passage has often been interpreted incorrectly by pre-new perspective protestant scholars. The (mis)interpretation of this passage has all too often been used to proof-text against Roman Catholic, and new perspective interpretations of Paul's writings (as they do with Phil 3:9 also).