Withdrawal was the way of the Pharisees. Anxious to apply the law to details of everyday life, they had a false understanding of holiness, imagining that mere contact with evil and evil  people would bring contamination. And a form of Christian pharisaism or separatism has lingered in the church. It has often been due to a passionate longing for holiness and a zeal to preserve Chrsitian culture from destruction by the wicked world.
          - John Stott