Daylight without a source?

In GN1:5 God introduces us to daylight, but does not mention a light source.

The word "sun" does not appear in the KJV nor the NASB until Genesis 15 after the flood. We often assume the sun is made during the fourth day, but that is only because God describes a visible light source for daylight. IF we trust Genesis, that greater light of the fourth day is the sun, just as trusting God and Genesis that daylight of the first day is true daylight tells us that daylight is from the same source mankind experiences.

The text is teaching that God Himself is the Source of all things, including light and daylight. That He makes use of a greater light which rules the daytime is incidental to the character of God being introduced. The sun was of course an object of worship and a false God to the Egyptians, and Genesis is correcting that false teaching.