In the mid 1990s, George Barna startled the church with what he termed “one of the rudest awakenings I have ever received." And what's that? It’s this: “Half of all adults who attend ...churches on a typical Sunday morning are not Christian!” Churches are filled with individuals who by reason of tradition, misinformation, demonic deception or something else have never come to a grace-based relationship with Jesus Christ. They are “lost in church.”
My church where I am right now is very evangelistic. And we're an active part of reaching the lost outside the walls of our local church. But there's this pressing need that Barna has exposed: up to one-half of the people going to church week after week are not Christians -"lost churchgoers!" As his research indicated, the need for "intra-evangelism" (evangelism within the walls of the church) is huge.
It's the Matthew 7/21 Window - the lost in the church. "Not everyone who says to me, 'Lord, Lord,' will enter the kingdom of heaven, but only he who does the will of my Father who is in heaven." The passage does imply that there will be those who'd get church or religion, but they don't get Jesus! I do used to think that I find the lost only outside the church fellowship. I can better see and understand now what's going on. My eyes are widely opened.
This explains why chaos happens within the church. Week after week, people go to church. Everything looks fine, but intimacy with God dries up. Gossip among churchgoers. Self-seeking ministers and workers. Fornicating worship leaders. Hypocritical, undisciplined, no passion for the lost. Indeed, behind the mask of outward spiritual church life, may lie a great darkness and lostness of soul.
He that believeth on the Son hath everlasting life: and he that believeth not the Son shall not see life; but the wrath of God abideth on him. ~ John 3:36 (KJV)
Check and view powerpoint on "Are You Lost in the Church?" plus many other helpful materials from the website www.lostinchurch.com to understand the issue better.