Fear or timidity is the prolongation of life.
Pain is the preserver of the instrument (of the human frame).
Fear
85.
Just as courage is the danger of life, so is fear its safeguard.
Body and Soul
86.
Let him who wishes to see how the soul inhabits its body observe what use the body makes of its daily habitation; that is to say, if the soul is full of confusion and disorder the body will be kept in disorder and confusion by the soul.
87.