Allâh is the Extensive Light of the heavens and the earth. His light can be compared to a (lustrous) pillar on which a lamp is put. The lamp is inside a crystal globe. The globe of glass is as if it were a glittering star. It (- the lamp) is lit by (the oil of) a blessed olive tree which belongs neither to the east nor to the west (rather welds the whole world in its fold). Its oil is likely to glow forth of itself even if no fire touch it. This (lamp) is a combination of many lights over and over. Allâh guides towards His light whoever desires (to be enlightened). And Allâh sets forth excellent parables for the people, and Allâh alone has full knowledge of every thing. - Quran 24:35