To separate theology and ethics is to understand neither. (I read that in a book somewhere.) The affirmation "Jesus is Lord" is as much ethical as it is theological. Indeed it's ethical because it's theological, and vice versa.
Seeing things this way opens up a whole new world as we read the New Testament. I don't think Paul wrote Romans so that the church in Rome would know his gospel before he came to them. I think he wrote it so that the Jews and Gentiles in the Roman church would just get along. How ironic that we have turned Romans into a theological treatise (I use "theological" in the worst sense of the word) which we then use to cause division rather than unity. If Paul was "doing theology" in his Roman epistle he was doing it in order to form a community characterised by love - love for the God who has manifested his love for us through Jesus and love for each other through the connecting power of the holy spirit. Paul as abstract theologian just doesn't cut it.
I understand that N.T. Wright has used Philemon as the foundation for his forthcoming book on Paul. This is a master stroke. We tend to shy away from Philemon because it isn't happy hunting ground for abstract truths that we can disagree over. In this short letter we can't so easily separate theology and ethics as we think we can in the other epistles, and this makes us uncomfortable. But the letter to Philemon is a beautiful glimpse into the purpose behind Paul's ministry. It was the ministry of reconciliation. Reconciliation of human beings to God, and human beings to each other. Slave and master become one. Jew and Gentile become one. Man and woman become one. That's a picture of the church right there.
Paul was, after all, a church planter, and he set up churches in order for them to display the power of the gospel through love. He wrote to these churches to remind them of that inextricble connection between gospel and love, or theology and ethics. Irony number two - how many churches today are founded on division? How many are planted in order to be separate from fellow believers? Living in Northern Ireland has been a wonderful experience so far, but it also a reminder of how far we are from that oneness that Jesus so fervently desires for us. We tend to use doctrine to draw distictions, but the best purveyors of doctrine know that it can and should be used to "do" something entirely different. Consider these thoughts from Ellen Charry:
The theologians who shaped the tradition believed that God was working with us to teach us something, to get our attention through the Christian story, including those elements of the story that make the least sense to us. They were interested in forming us as excellent persons. Christian doctrines aim to be good for us by forming or reforming our character; they aim to be salutary. They seek to form excellent persons with God as the model, and this is in a quite literal sense, not as metaphors pointing to universal truths of human experience that lie beyond events themselves. In other words, I came to see that the great theologians of the past were also moralists in the best sense of the term. They were striving not only to articulate the meanings of the doctrines but also their pastoral value or salutarity – how they are good for us.
Doctrine at its best sweep us into a drama where we are called and equiped to play a role not unlike that of Jesus in the Gospels. This is what Paul's life and letters were all about: forming communities of "excellent persons", or as he might say himself, persons who are "mature in Christ". Lose sight of this and we lose sight of salvation.