Genesis 1:4

1:4 God saw that the light was good, so God separated the light from the darkness.

Genesis 1:6

1:6 God said, “Let there be an expanse in the midst of the waters and let it separate water from water.

Genesis 1:18

1:18 to preside over the day and the night, and to separate the light from the darkness. God saw that it was good.