Genesis 1:3-5 Then God said, “Let there be light”; and there was light. And God saw the light, that it was good; and God divided the light from the darkness. God called the light Day, and the darkness He called Night. So the evening and the morning were the first day.
God said let there be light, light was. The first thing God did to bring the world out of chaos was illuminate it. Light and truth always defeats darkness. Notice, the creation of the sun and moon is the 4th day. This has a feel for what we read in Revelation 21 & 22, where there will be no sun or moon, for the Lamb will be the light. These days also, are 24 hour literal days. God is light and in Him is no darkness at all.