John MacArthur, On How the Church Works Together

“Our physical bodies cannot function properly or safely if each member does not correctly communicate to the others. If our brain were suddenly to start giving false signals to our feet, we would stumble or walk in front of a moving truck instead of stopping on the curb. If it falsely reported hot and cold, we could freeze to death because we felt too warm or be scalded in a hot shower while feeling chilly. If our eyes decided to send false signals to the brain, a dangerous curve in the highway might appear straight and safe, and we would crash. If the nerves in our hands and feet failed to tell our brain that injury was occurring, our foot could be mangled and our fingers burned without our knowing it.” (commentary on Ephesians)