God dispels the darkness of ignorance and hence we are sure that at least he is not darkness.
But then is God light?
Now when we think of light, we think of light that is visible to our eyes. And something that is visible to material eyes is also material. But God is Sat-Chit-Anand i.e full of bliss, knowledge and eternal.
hence the answer here would depend on what you call as light .
- If we are referring to light as perceived by our eyes then No. God is not light.
- But if I say here light as knowledge then yes God is Knowledge,God is light.
As a blazing fire turns firewood to ashes, O Arjuna, so does the fire of knowledge burn to ashes all reactions to material activities.
We cannot apply the idea of our limited mind to God. God is beyond the imagination of our mind. Nor we can think of him as something black or white as in we cannot say that if He is not Darkness then He must be light.
So who is God?
vedanta Sutra says
JanmaDyasya yatah (1.1.2)
Meaning:From whom birth etc.
God is He from whom everything emanates i.e. from whom light, darkness etc everything has come.Everything that our mind can possibly think of and not think of emanates from Him only.
What is light?
In very simple terms light is energy of God; Material energy to be specific. And God is energetic. Just like Sun is the Source of Sunshine and Sun Shine is his energy.
But if you call Knowledge of self, Knowledge of God as light then that is God. Knowledge of God and God are non-different.
In Gita Krishna Says
By Me, in My unmanifested form, this entire universe is pervaded. All beings are in Me, but I am not in them. And yet everything that is created does not rest in Me. Behold My mystic opulence! Although I am the maintainer of all living entities and although I am everywhere, I am not a part of this cosmic manifestation, for My Self is the very source of creation.
So Krishna says that by His energy he pervades the entire universe and yet He is not the part of this material cosmic creation. he is beyond it. He is fully spiritual.
later in Gita Krishna says
That supreme abode of Mine is not illumined by the sun or moon, nor by fire or electricity. Those who reach it never return to this material world.
So to answer your query in Nutshell.
God is neither light nor darkness but the very Source of both. Light or Darkness are just expansion of His energy or one of His unlimited energies.
But Light of Knowledge(Knowledge of self) is God.