God is the light of the heavens and the earth. His light may be compared to a niche containing a lamp; the lamp within a glass, the glass like a radiant star; lit from a blessed tree – an olive tree that is neither of the east nor of the west. Its very oil would almost give light even though no fire had touched it. Light upon light! God guides to His light him that wills [to be guided]. God propounds parables for all people, since God alone has full knowledge of all things.