Why did Paul write his letters? Surely it was not to dispense information solely for the purpose of the cognitive consumption of individuals in the communities he was writing to. That is to say, Paul had way more in mind than instructing us in doctrinal things that we must cognitively assent to, to be saved. Every part of every letter he wrote was written with the intention of constructing healthy Christian communities. That should cause us to ask, 'what roll does theology play in building community?'
One interesting proposal comes from chapter 3 ('Reading Paul: Myth, Ritual, Identity and Ethics') in Solidarity and Difference by David Horrell (which is backed up at length with arguments from the social sciences on group formation and identity - an excellent read that I highly recommend) where he argues that theological statements should be seen as identity-descriptors and group norms needing to be affirmed constantly, not indicative statements to be held as true or false (p. 94).
While I don't agree with Horrell completely, I think he's on to something. I would rephrase his conclusion to say that theological statements are not purely indicative statements to be held as true or false. They additionally function as identity descriptors and group norms which have massive implications on the way we live. This means that both what we believe and how we act defines who we are as a group. It controls who is considered inside and outside (conformity also impacts the rolls that one can take in the group as more important rolls require greater conformity to group norms).
I believe, though, that the relationship between boundary defining doctrine and boundary defining behavior is much closer than we might initially think. In addition to being facts to be believed, doctrines are ethical imperatives (I think this is in generally consistent with Horrell's point, although he may waver at extending it as baldly as I am). They are realities to be lived out. No doctrine can be said to be understood if it is not lived out. But what does that look like? What does it mean to live out a doctrine and how does it build community? We'll answer that in a post later this week when we look at an example of living out a specific doctrine, namely imputation.