what is the pointe of church?

I'm currently reading a book in seminary about Karl Barth and John Yoder, some interesting theologians.  They believed that the mission of the church is simply to bear witness to Jesus Christ.  They further this thought by stating the reason Jesus formed the basis for Christian communities was that the witness of Christ's love HAD to be a community (church) in order to be clear.  Certainly this simple mission can be interpreted and acted upon in several ways, but if you were to think about everything your church does, examine every function with the question; "does this bear witness to Jesus Christ?"... would this theory conform to your church?  Should it?