New Defender's Study Bible Notes
1:3 God said. As the “Spirit” of God “moved” (Genesis 1:2), so now the Word of God speaks in Genesis 1:3. The result is light, the energizing of the vast cosmos through the marvelous electro-magnetic force system which maintains all structures and processes in matter. These varied energies include not only visible light, but also all the short-wave radiations (ultra-violet, x-rays, etc.) and the long-wave radiations (infra-red, radio waves, etc.), as well as heat, sound, electricity, magnetism, molecular inter-actions, etc. “Light,” the most basic form of energy, is mentioned specifically, but its existence necessarily implies the activation of all forms of electro-magnetic energies. Light was not created, since God Himself dwells in light. On the other hand, He created darkness (Isaiah 45:7).
The existence of visible light prior to the establishment of the sun, moon and stars (Genesis 1:16) emphasizes the fact that light (energy) is more fundamental than light givers. God could just as easily (perhaps more easily) have created waves of light energy as He could construct material bodies in which processes function which generate light energy. The first is direct (since God is light!), the second indirect. For the creation of such light generators, see note on Genesis 1:14.
1:4 darkness. That these rays of light energy included the visible light spectrum is obvious by its separation from the newly created “darkness.” That most of this visible light emanated from one direction in space and, further, that the newly-sphericized earth began now to rotate on its axis, is shown by the establishment of a cyclical succession of “Day” and “Night,” which has continued ever since.