Another question from a George Fox student, Elizabeth: "My experience with suburbia is that there are few Christians in suburbia who have any kind of "missionary impulse" (pg. 30) and if a "critical mass" (pg. 52) were reached in a neighborhood it would result in a Christian clique forming rather than an embodied witness of the body of Christ to the neighbors. How do you define "critical mass" and can you offer any suggestions on how to inspire a "missionary impulse" in such a group?"
Elizabeth - alas, yes, there are too few suburban Christians that are truly missional about their suburbs! Most suburban churches are concerned about evangelism and outreach, but that's somewhat different than seeing your suburb missiologically and actually exegeting/exploring one's suburban culture for the purpose of living and ministering there incarnationally.
A "critical mass" of Christian presence in a neighborhood naturally would look different in different situations, so I don't think I have a specific guideline or concrete number of how many or what percentage. I agree, there's certainly a danger of Christian cliquishness (which is true of any church or Christian community). But the alternative is usually that there's no visible Christian presence or witness at all. So better to build a Christian community and to guard against it becoming ingrown and cliquish.
How to inspire a "missionary impulse"? Here's one practical idea. I love what Todd Hiestand's church, The Well, in suburban Philadelphia did this past summer - they had a short-term mission trip to their own suburb. Think of how much anticipation and preparation the average church does for an overseas short-term trip. People raise money, write prayer letters, learn basic language phrases, watch videos, try making indigenous food, get acquainted with culture, music, clothing, etc. Well, imagine if a suburban church invested a similar amount of time and energy preparing for a mission trip to their own suburb! I think people would start to view their suburban context very differently if they went through the exercise of preparing to be short-term missionaries to their suburban area.