my own personal guess.
Jesus declared that he was “the light”
I interpret that as the light in Genesis 1:3
quote “And God said, “Let there be light,” and there was light.”
So light has been with God since the beginning. And Jesus is the light. Just my personal belief.
The late Rev. Bill Randles who used to post here on FR had a great sermon where he listed the attributes of God.
God is love
God is light
God is eternal life and then one more
Jesus Christ came down to us in the flesh and remains so.