God is the light of all on high and all on earth. An example of His light is like a niche that contains a lamp, that lamp being in a certain kind of glass. And it is as if that glass were a brilliant star, lit from some blessed olive tree, neither western nor eastern. The oil of that tree will almost shine without being touched by any flame.  He is a light above any light, and guides to His light whoever wants it and whomever He wishes to bring to it. God gives metaphors for the benefit of people and is discerning of all things.