Image by ladybugbkt via FlickrThink of the brain as a giant swimming pool. On one end it is deep, the other, shallow. The shallow end has a wading pond for those who cannot swim and detached, but nearby, is the hot bubbling sauna.
When a person is introduced to Christianity, they are encouraged to dip their feet in the warm waters of the wading pool. Slowly, they put their legs in a little further until they get used to the temperature of the water. Eventually they immerse themselves in the warm water and become baptized. They are considered "children" in the eyes of god and are encouraged not to drift from the shallows.
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