If you were to take a straw poll on what the main idea of the book of Romans is, the most common response would be justification by faith or maybe a presentation of the gospel. Out of all the letters of Paul, Romans has garnered far more ink than any other. And with good reason . . . it is one of the great works in the Christian tradition. Last semester, I took a Greek exegesis class on the first half of Romans and over intersession I took a class on the New Testament epistles. A large number of sources that I consulted for these classes made the assertion that Romans was the least occasional of Paul’s letters. By this, it simply means that Paul was not addressing any specific issues in the church, or if he did, he was addressing very few. They make this claim because Paul did not plant the church in Rome nor had he even visited it. Then they have to explain away the long list of personal greetings in the last chapter. They usually say something to the effect of Paul was trying to establish his authority and relationship with them. This may quite well be the case. However, it also allows the letter to be interpreted very objectively and that’s how we end up with the presentation of the gospel as the Romans Road or something like that. If Paul is not addressing particular issues in the church, then this makes sense of his presentation of the gospel to them and it translates nicely to today then as well.
However, there is a problem with this. Paul IS addressing a particular issue. Even scholars who acknowledge it still claim it is the least occasional of his letters. They would say that because Paul did not start the church, he would want to present the gospel to them. But they were a church. It’s not like they were a cult. The letter was written to the church at Rome and there’s no hints in the letter that they had heard a false gospel. So why would Paul spell out the gospel to them if they already knew it. That is why I would disagree with the argument that this is a systematic exposition of the gospel.
Instead, Paul is addressing the Jew-Gentile divide in the church. Jews had been kicked out of Rome by the emperor Claudius in 49 AD. However, they would return in 54, after Claudius died and the edict was reversed. Thus, Gentiles had led the church in the Jews absence. Now, a number of Jews were returning and trying to assimilate back into the church. Maybe they were even trying to regain their positions of leadership. Thus, at the heart of Romans, the main issue Paul is addressing is reconciliation between Jews and Gentiles. If this is the framework through which we read the epistle, I think the pieces of it seem to fit together better. Try reading Romans with the backdrop of Jew-Gentile reconciliation instead of an objective presentation of the gospel.