"And God said, Let there be light: and there was light." Gen. 1-3.
Material history has sought to attribute the light we behold with the physical senses to this declaration of God, but if we search material history, we will find that we can come to no positive conclusion as to what light is. It is a theory to begin with, and a guess to end with.
Some suppose it to be particles of matter emitted or projected from a luminous body; others suppose it to be the vibrations of the atmosphere, etc. But when we look at the idea which God expresses, and understand that it truly does have a Principle,— when we learn that there is but one Principle, and that is found in God, is God,— we can begin to get some definite idea of what light is.