It is interesting to me to observe that Jesus never actually gave an evangelistic message (so far as the gospels tell us), nor did He ever give an invitation (as we know it -- see Matthew 11:28-30). When Paul speaks of the conversion of the Ephesians he describes it as "learning Christ" (Ephesians 4:20). Frankly, if we are teaching God's Word as we should people will be learning of Christ, including the lost. I have seen a number of people saved by listening to teaching addressed to believers.
For these reasons I would say that many churches need to quit trying to attract unbelievers to church, seeking to win them to Christ there, but they should start teaching believers the Scriptures, helping saints to know and develop their spiritual gifts, and then sending them out into the world with the gospel.
-- Bob Deffinbaugh