My friend John Armstrong is a church leader who has traveled the distance from the separatist, sectarian fixity of fundamentalism to embrace the kingdom-centered vision of the church and the call issued by a number of Bible-based theologians and missiologists during the past half century.

What vision is this? It is the one that views the visible church as a single worldwide, Spirit-sustained community within which ongoing doctrinal and denominational divisions, though important, are secondary rather than primary. In this vision, the primary thing is the missional-ecumenical vocation and trajectory crystallized for us by our Lord Jesus Christ in his teaching and prayer and illustrated in a normative way by the Acts narrative and much of the reasoning of the apostolic letters.

Evangelicals have always urged that the church of God is already one in Christ but have typically related this fact only to the invisible church (that is, the church as God alone sees it).  All too often, they have settled for division in the visible church (the church on earth, as we see it) as at least tolerable and at best healthy. The vision Armstrong offers, however, perceives by exegesis that the unity of Christians, which Jesus prayed that the world might see, is neither unanimity nor uniformity nor union (as he neatly puts it) but loving cooperation in life and mission, starting from wherever we are at the moment and fertilized and energized by the creedal and devotional wisdom of the past. Thus the internal unity of togetherness in Christ may become a credibility factor in the church’s outreach, just as Jesus in John 17 prayed that it would.

Embracing this vision will mean that our ongoing inter- and intra-church debates will look, and feel, less like trench warfare, in which both sides are firmly dug in to defend the territory that each sees as its heritage, and more like emigrants’ discussions on shipboard that are colored by the awareness that soon they will be confronted by new tasks in an environment not identical with what they knew before. There they will all need to pull together in every way they can. The church in every generation voyages through historical developments and cultural changes, against the background of which new angles emerge on old debates and truths may need to be reformulated in order to remain truly the same as they were. Not to recognize this is a defect of vision on our part.

This perception, not surprisingly perhaps, disturbs persons brought up to believe that Bible-based doctrinal faithfulness counts supremely (yes, indeed, right so far), and that some form of ahistorical fundamentalist fixity was, is, and always will be the doctrinal last word. John Armstrong knows; he has been there.  His corrected and corrective vision generates deep suspicion and an onslaught against its proponents as confused compromisers.  Both he and I have learned this by direct experience. Some years ago, in One Lord, One Faith, Rex Koivisto made many of John Armstrong’s points and was effectively ignored. I hope this book will not be ignored but will have the influence it deserves. Aspects of North America’s future—aspects, indeed, of the honor and glory of Christ in this century—may well depend on whether or not it does.

— J. I. Packer, Advent 2009