I meet many believers who seem to think that the local church is there to protect them against the ills of society. In fact, whether it is explicitly said, it is certainly implicit in the kind of programming the typical church does that keeps people busy at church and leaves very little time for engagement with their community, unbelieving friends or other activities (sports being the notable exception). There is a bunker mentality among many believers that sees the church as their protection against the evils of our world.
It is a sadly mistaken view of what God intended for us as believers. If Jesus is our model all one needs to do is look where he spent much of his time and with whom - sinners. And I am talking corrupt officials (tax collectors), prostitutes, adulterers, and everyone that the pharisees found objectionable. In fact, Jesus did not fear the world, does not want us to forsake the world but does want us protected from the evil one. Thus He prayed in His high priestly prayer of John 17, "My prayer is not that you take them out of the world but that you protect them from the evil one."
Thus a lifestyle of avoidance of the world is actually directly contrary to the example of Jesus and His will for our lives. For without engagement there is no opportunity for the good news of the gospel to become known or for the Gospel to transform people, communities and institutions. In fact, it is genuine engagement with people that Jesus modeled and the New Testament teaches. It is engagement with our world on behalf of Jesus rather than avoidance that is His desire for us.
Here is an interesting question: How many unbelieving friends (true friends) do you have and how much time do you spend with them? For many Christ followers that is an uncomfortable question since the answer is few or none. That is a life of avoidance, not engagement. When Jesus tells us to go into all the world and make disciples He is not saying "write a check to support a missionary far away" although that is a good thing to do. The "Go" is to all of us where we are, with whom we work and live and play and it is everyone's job to make disciples.
For the tech savvy, the combined Klout score of your congregation (see www.klout.com) is the combined number of meaningful relationships your congregation has with unbelievers. Unfortunately, the Klout scores of most congregations is terribly low. But it needn't be.
If you are a pastor or church leader, ask the question: "Is the mentality of our congregation more about avoidance or engagement?" And, "What is basis for your answer?"
The purpose of the church is not to avoid the world but to overcome the world.
(Written from Berlin, Germany)