On Boundaries and Exclusiveness: A few quotes/teasers from Brian McLaren's chapter from The Secret Message of Jesus on the subject ('The Borders of the Kingdom' pp. 162 ff.):

'How can some people interpret Jesus' message as exclusive, while others see it as the most radically inclusive message in human history? What is the truth about Jesus' message: Is it, like most religious messages, about in-groups and out-groups, us versus them, condemnation and exclusion? Or is it indeed an embracing message with good news for all people? Can any meaningful kingdom, including the kingdom of God, exist with no boundaries, no outside?'

'There are two dangers: hostile exclusion and... naive inclusion. You can't solve one problem simply by going to its opposite; there has to be a third way that is different from both permissive, naive inclusiveness and hostile, distrustful exclusion... The kingdom of God seeks a third way... *purposeful inclusion*... [including] all who want to participate in and contribute to its purpose, but it cannot include those who oppose its purpose.'

[Re the attempt to stop someone casting out demons 'because he is not one of us']: 'Again, this is classic boundary-erecting behavior of an exclusive in-group. Jesus replies, "Do not stop him... for whoever is not against you is for you".'