This lengthy quote comes from Biblical Authority after Babel: Retrieving the Solas in the Spirit of Mere Protestant Christianity by Kevin VanHoozer. It only costs just over six quid on Kindle and is a book that any aspiring student of theology or the reformation (especially, if you think yourself as both) should read.
Andrew Walls, a historian of mission, views translation into vernacular languages as the principal means by which the gospel is transmitted. Walls’s special interest is the rise of Christianity in the non-Western world, and though he does not mention Luther, I see no reason why we should not consider Luther as part of the gospel’s missionary advance. Luther translated and contextualized the gospel—which is to say, retrieved it—into the vernacular language and cultural situation of his day. Theology is always missiological to the extent that the search for understanding requires us to speak that understanding into new contexts. The Reformation thus appears in this light as a missiological retrieval of the gospel as set forth in the original languages of the Bible. Walls’s understanding of mission and transmission helps us to see better how retrieval looks back creatively in order to move forward faithfully. Vernacular translation—the attempt to contextualize the gospel in a particular language—results in a net conceptual gain for the whole church. We see this at Nicaea, when the West and East had to come together to articulate the Son’s relationship to the Father. I think that we also see it in the Reformation. Consider the way Walls describes the process of transmitting the faith: “As Paul and his fellow missionaries explain and translate the significance of the Christ in a world that is Gentile and Hellenistic, that significance is seen to be greater than anyone had realized before. It is as though Christ himself actually grows through the work of mission.” To retrieve the Reformation, then, is not to repeat but to translate it into our new cultural contexts, thus enlarging our understanding of its achievement.