Why would Paul write his longest letter to a church he had not founded or even visited? This expositor believes the answer lies in its history, culminating in a major crisis which could have split the whole church into two denominations. Originally Jewish (Acts 2:10-11), it soon attracted Gentiles, who were left on their own when Claudius evicted all Jews (Acts 18:2). In their absence a teaching emerged which we now know as 'Replacement Theology', believing that God has rejected the Jews and turned instead to the Christian Church as his chosen people on earth, a view which, alas, is now widespread. Paul's carefully argued answer shows how much believing Jews and Gentiles have in common, both in sin and salvation, in flesh and Spirit. This approach treats 'Chapters 9-11', (divisions never in his letter) as an integral part of his appeal, reaching its climax in a threefold challenge to the arrogance of the Gentile believers in Rome (11:18, 20, 25) in not warmly welcoming back into the fellowship the Jews who were allowed to return under Nero. This 'key' unlocks the whole epistle, from the solemn warning that believers can lose their salvation (11:20-22) to the careful instruction on how to live with 'disputable matters' such as diet and days (14:1 - 15:13); and ends with so many commands to greet each other with 'a holy kiss' (16:16). However, as with most of Paul's practical counsel, all this is firmly rooted in sound 'gospel' theology.