A helpful set of questions re unity has been posed by my friend and colleague, Bosco Peters:
"Is it just possible that it is the attempt to list off, in ever tighter "detail" "beliefs" rather than living the way Jesus lived that inevitably leads to ever greater division and has always done so? And that, hence, the search for lists of agreed beliefs is not going to lead to unity?"
I suggest, in response, that it is not difficult to answer both questions affirmatively while acknowledging a further question lies within the citation: what does it mean to live the way Jesus lived?
It is not just that we need to quickly set aside a whole lot of things that Jesus did which no serious follower of Jesus thinks we need to do (live as a first century Jew re religious practices; live as a first century Palestinian re cultural mores; undergo the baptism of John; only celebrate eucharist once in a lifetime), but also that we are faced with (at least) two things to ponder carefully.
First, doctrine has mattered to followers of Jesus at certain points in Christian history in which difference has not been about 'lists'. Arians, for example, were serious, devoted followers of Jesus. But something in the following was troubling to the point of dividing rather than unifying. (As I understand it) Arians would not follow the orthodox to the throne of God and worship the Son as one with the Father. Or, to take a more recent example, Mormons are 'latter day saint' followers of Jesus, but something in their following of Jesus is troubling to orthodox Christian followers of Jesus, and so we are not united by merely following Jesus together.
Secondly, doctrine should matter to followers of Jesus in at least this sense: doctrine is about teaching and teaching was what Jesus did! Far from 'doctrine' being pitted against or simply distinct from 'following Jesus', we should ask how doctrine serves and supports our following of Jesus because it lays out and clarifies what Jesus taught (both directly in his lifetime and through the Spirit of Jesus working in the apostles beyond his resurrection). Eucharistic and baptismal doctrine, for example, should deepen our understanding of both Jesus' commands to 'do this' and to 'baptise' and of the support baptism and eucharist provide for our life in Christ. Ecclesiology - as great a dividing set of doctrines as any!! - essentially sets out what it means to be followers of Jesus together.
Well, much more could be said here. My present theme is 'unity'. My point here is that if doctrine as conceived in this church and in that one is dividing us, rather than uniting us as followers of Jesus, then it is very likely that we have developed an understanding of doctrine in relation to following Jesus which is itself divided from discipleship. A root and branch reform of doctrine which ties doctrine to discipleship so that doctrine serves our living like Jesus would greatly assist our reunion as Christians.