If the sun, moon, and stars were not created until the 4th day, where did the light in the 1st creation day come from? The Bible gives us a clue to the source of the light.
"For God, who commanded the light to shine out of darkness, hath shined in our hearts, to give the light of the knowledge of the glory of Godin the face of Jesus Christ." -2 Cor.inthians 4:6
The Bible is telling us that God can command light out of the darkness and that light is coming from the GLORY of GOD in the face of Jesus Christ.