Why is it so much more difficult in the West? Why can’t we imagine being a community of Christ’s followers without a building or formally trained and accredited clergy? Whenever I raise this issue in seminars, people regularly remind me that house-based groups of fifteen or so without proper accreditation and training can lead to heresy and cultish practices. But the fact remains that nearly every major heresy that has beset the Christian church has come from recognized church bodies whose leaders were properly accredited by their sponsoring hierarchies. Conversely, virtually every new movement among people hungering for a deeper knowledge of God has been rejected, quashed, or destroyed by the “church” of its day, and its leaders have famously been excommunicated or martyred for following the missional impulse of God. Being part of a recognized denomination or organization by no means guarantees biblical purity. The fledgling churches living out their faith in those Sudanese refugee camps are every bit as legitimate as the congregation of Canterbury Cathedral.
(from Exiles: Living Missionally in a Post-Christian Culture)