The very first thing that God created was light. It is fundamental to the structure of space and time in this universe. Nothing else would exist without light. Not only does it give us the ability to see things, but the universe itself depends on the operation of electro-magnetic radiation, including the visible spectrum that we perceive as light and colour. Without light there would be no life on this planet, no warmth, no plants, no animals, no food, no mobile phones and no internet.
Even before the creation of physical light, before the creation of the physical universe, there was, and always will be, spiritual light. Just as physical light is needed to see the universe, spiritual light is needed to see or know anything about God.