Barth on defining the authority of scripture, and issues in the Anglican communion

Barth is notorious, particularly amongst evangelical scholars, for his view of the authority of scripture. He is right, I think, to argue that scripture's 'authority' is relative to the authority of Christ. This is precisely why his threefold definition of the Word does not privilege scripture, but acknowledges its principal witness to the 'wordiness' of Jesus (John 1 - a passage of which Barth was very fond). Where I think his approach to scripture becomes more complicated, and difficult to understand, is in passages relating to moral authority, such as this one:

All biblical imperatives - and we do not say this to impugn the authority of the Bible but to define it - are addressed to others, and not to us, and they are addressed to others who differ greatly among themselves, to the people of Israel in different situations, to the disciples of Jesus, to the first Christian churches of Jews and Gentiles. Their concreteness is that of a specific then and there...This means, however, that no biblical command or prohibition is a rule, a general moral truth, precisely because it comes to us as witness to the absolutely concrete real command. (Ethics, p.80-1)  

At once I see the theological presupposition that leads Barth to argue against the generalizing of the divine command - to prevent supposed 'access' to the will of God without encounter with God himself - and I think this is a correct move. But, I also see the potential problems if the scriptures are divested of authority in the church and am left wondering what normative role the Bible could have in Barth's schema. Why should we read it, especially with regard to ethical questions? Barth's response is that it bears witness to the command of God (p.82) - and so in that sense reading scripture may be, what Nigel Biggar calls, 'an aid to hearing' God's command for ourselves. But this still leaves me with, as yet, unresolved questions about the actual task of reading scripture - especially when we do that together as the Church seeking moral guidance. How do we resolve our disagreements on issues when we read the same texts?

The problem is demonstrated acutely in the present situation in the Anglican communion. Reading scripture together on issues of sexuality, or womens' ministry (note: I'm not conflating these into the same issue), throws up huge questions about the way we use scripture in ethical deliberation, and how we aim to hear God's voice in and through its witness. Some of these questions are hermeneutical and exegetical, but some are also theological. What place does scripture have in the moral life of the church? What does the theological category of witness do to the way we read the Bible ethically? My tentaive conclusion is that the common groud we must share is not in the way we read, but the fact that we read together - and ultimately pray together. Prayer forces us beyond the pages of the Bible to the God who breathes life into it. If Barth is right, then it is in allowing scripture to turn us toward Christ in prayer, together in our disagreements, that some way forward may be forged. But then, prayer is itself is as big a mine-field as biblical authority...

I will revisit these thoughts myself in coming days, but I'd be interested to hear yours.