"To begin, we may recognize that Christian Scripture has no authority outside the church, so that we need not look or argue for it there. As the old Lutherans put it, Scripture's authority is to save, and by salvation they meant only the specific fulfillment proclaimed in the church. Indeed, the documents assembled as Scripture belong together as one book only because the one church assembled them to serve its one mission to speak the gospel, whether to people in proclamation or to God in prayer. Apart from this purpose, there is no reason whatsoever for these particular documents of ancient Near Eastern religion to be under one cover. When academic study abstracts from this churchly purpose, the Bible quickly falls to pieces: on the one hand, into 'Hebrew Scripture,' and on the other hand, into a miscellaneous pile of evidences for Christian origins that can be added to or subtracted from at the whim of the scholar.
"We may next pick up the possibility opened by [Johann] Musäus, doubtless pushing beyond anything he would have countenanced. Mere observation of the church's life must discover that as Scripture tells the story of God and ourselves, it acquires many different roles in the church's life, all of which can come under Musäus's rubric of Scripture's free power to evoke faith. It is especially the Old Testament, with its rich language and stories, that acquires these roles, since it most clearly represents the Word of God's antecedence to the church.
"Scripture, thus, exercises authority to create faith when we pray the psalms and other prayers of Scripture or make new prayers on their templates. Scripture exercises authority to create faith when a hard text is laid on the preacher and he or she tries to say what it says, successfully or not. Scripture exercises such authority when we simply read or hear it -- regardless of our subjective motivation at the moment. Scripture exercises such authority when our communal rhetoric is formed around its laws and stories -- for example, when a mere reference to 'Gilead' can call up a whole narrative style and morale. Scripture exercises such authority when the rhythms of its prosody determine the rhythms of churchly music. Scripture exercises such authority when its way of talking about politics of sexuality shapes a believing construal of these central features of humanity. Scripture exercises such authority when the plot of the story it tells shapes the plot of our services. And one could go on with this list. In general, we could say that we are open to Scripture's authority to create faith when we intellectually and spiritually hang out with it, on the corner labeled 'church.'
"In the summer of 1963, I and some other then 'younger' theologians were variously occupied in Harvard's libraries, while Cambridge's NAACP was recruiting for what turned out to be the 'I have a dream' march in Washington. We dithered. On the Sunday before the march, at the service most of us attended, the lectionary Gospel was the parable about the son who said, 'I go' and went not, and the son who said, 'I go not' and went. The preacher then mounted the pulpit and simply repeated the address of the sign-up center. That afternoon we marched straight there. This too was scriptural authority in action, to mandate and liberate, or in the Lutheran phrase, to be 'law and gospel.' "
--Robert Jenson, "On the Authorities of Scripture," Engaging Biblical Authority: Perspectives on the Bible as Scripture (edited by William P. Brown; Louisville: Westminster John Knox Press, 2007), 58-59