Wright makes better sense of Romans 4 than his detractors. The typical old perspective reading has Paul use Abraham as a subtopic in proving his thesis that humanity can only be made right with God by faith in Christ. Wright sees Romans 4 as an explanation of the Abrahamic covenant which is essential to God’s one plan to deal with sin through Israel. Wright’s reading is superior to the OPP because the OPP reading sees Abraham’s ungodliness relating to an ethical deficiency. However, Paul quotes Psalm 32, where David asks for forgiveness and yet identifies himself as godly. It is more likely that godly = being a Gentile. This makes sense of verse 10 and also the way that Abraham is described in the book of Hebrews and Genesis. It is interesting to note that the phrase “counted it to him as righteousness” is not only mentioned in Genesis 15:6 but also in Psalm 106:30-31 in reference to Phinehas. Phinehas was a circumcised believer who in his zeal for the covenant, slew a Gentile and a compromised Jew for unlawful intercourse. He was a Jewish covenantal hero. Paul is saying that Abraham has the same status as Phinehas – they are both faithful covenant members. Paul also mentions the justification of David. In order to understand this we need to see what Paul has said in Romans 2:25 that for the disobedient, circumcision becomes uncircumcision. David has put himself outside the covenant through his seduction of Bathsheba and his murder of Uriah. But God can bring him back in through faith. Mark Horne says it best: “And Paul’s whole argument has been that Israel is corporately apostate and thus no different than the nations. Rather, Israel with the whole world is weak and ungodly (in the full sense of that word), and it was precisely at that moment that Christ died for us (“For while we were still weak, at the right time Christ died for the ungodly.”) (HT = Mark Horne.)
Read the whole thing: Why Wright is Right « City of God.