There's a movement in today's "Christian subculture" towards isolation - home church - separation. Today I was reading in 1 Corinthians 5:9-11, and it talks about separating yourself from the sexually immoral person, the drunkard, the greedy person, the slanderer. A lot of times, people take this to mean that they should only hang out with church people. Sit in their little holy huddle, learning new Greek words, and having Vacation Bible School meetings.
But, Paul says he isn't "at all takling about people who aren't followers of Jesus". He was talking about the person in the church who says they're a follower of Jesus, have begun a life of following Him, but then are not living that way consistently - not changing. I loved how he said, in essence - "I'm in NO WAY talking about people who are still seeking".
The "Church" is not a building where people gather, it's people who are followers of Jesus. Out of that group - we shouldn't be best buds with people who say they're following Jesus but show no signs by their actions of really following Him.
But, can we be around and connect with people who aren't following Jesus, but are coming to the building for our gatherings and are sexually immoral, drunks, greedy, slanderers? By all means! Welcome them - connect with them - pray for and with them.
If we're called to be isolationists at all - it's to isolate us from the hypocritical people who claim one thing and live the polar opposite. It's from the religious people, the Pharisees. Often times, the very people who are trying to isolate themselves from "the world". Interesting.