Church is not a rival institution to family or state, it is a whole new world

"The systems of the world cannot contain or control the rival 'world' established by Christ in which the fundamental form of relation is the mutual construction of persons in the likeness of Jesus...By presenting itself as a new world, Christianity finds itself in its early years often in sharp conflict with family, synagogue and kingdom; but not as another society competing for a position alongside them....The Church claims to show the human world as such what is possible for it in relation to God- not through the adding of ecclesiastical activities to others, and not through the sacralizing of existing communal forms, but by witnessing to the possibility of a common life sustained by God's creative breaking of existing frontiers and showing that creative authority in the pattern of relation already described, the building up of Christ like persons"

Williams 'On Christian Theology 232-233