Genesis 1:4, 6-7, 14, 18
Genesis 1:14 NASB1995
Then God said, “Let there be lights in the expanse of the heavens to separate the day from the night, and let them be for signs and for seasons and for days and years
Genesis 1:18 NASB1995
and to govern the day and the night, and to separate the light from the darkness; and God saw that it was good.