Genesis 1 V 4 says, “and G-D saw that it was good“. Creator G-D saw light was good and declared it. This is very important. The first creation was good before Lucifer rebelled. This important truth can be overlooked if not careful.
Genesis 1 V 4b, “God separated Light from darkness.” It was important to encapsulate the light being and protect it from darkness. Creator G-D named the light being Lucifer.
Once G-D spoke light into being by voice and manifest it through The Word, the next step was to name it. Genesis 1 V 5 says, “God called the light day and the darkness he called night.“
G-D set distinct boundaries between light and darkness. Evening and morning was the first day.