Sorry I hope I am not talking to much lol. But this fascinates me.
The light itself on the first day does something:
Gen 1:3 And God said, Let there be light: and there was light.
Gen 1:4 And God saw the light, that it was good: and God divided the light from the darkness.
Gen 1:5 And God called the light Day, and the darkness he called Night. And the evening and the morning were the first day.
This light is divided from the darkness and gives us the day night cycle. Yet notice when God fills on day 4:
Gen 1:14 And God said, Let there be lights in the firmament of the heaven to divide the day from the night; and let them be for signs, and for seasons, and for days, and years:
Gen 1:15 And let them be for lights in the firmament of the heaven to give light upon the earth: and it was so.
Gen 1:16 And God made two great lights; the greater light to rule the day, and the lesser light to rule the night: he made the stars also.
Gen 1:17 And God set them in the firmament of the heaven to give light upon the earth,
Gen 1:18 And to rule over the day and over the night, and to divide the light from the darkness: and God saw that it was good.
these lights serve the same purpose as far and dividing light fro darkness. they are given to rule the day and the night. So remember Day and night exist before the sun moon and stars at it comes in day 1. Yet these lights are designed to give light on the earth and also have a purpose that the first light only does partially.
the first light give us the basic break between day and night. But these lights give more: and let them be for signs, and for seasons, and for days, and years:
So it would seem the sun moon and stars bring extra dimension from the light of the first day. These lights also rule over the light of day from day 1 and the moon and rules over the night when it is darkest.
Could the light and darkness of the first day literally just be a partition of time and the 4th day filles that partition with literal lights that are to govern those partitions and serve for times seasons etc.?
The reason I ask is this, The first three days everything we understand, for example: water, heavens, firmament, land, all these things are space and God fills these things in the last three days.
Could the light then simply be time boundary that does not get anything to govern it till day 4.?
Just putting the question out there, I don't know I have never thought of this before now and could be off by miles.