What is the theological message?
In Genesis 1? There are several:
1. Only one god exists -- Yahweh.
2. The Babylonian gods do not exist. Those gods were linked to specific physical things: saltwater, sweetwater, sun, moon, stars, plants, etc. Genesis 1 has all those physical things being created by Yahweh. Therefore that creation of the physical object destroys the Babylonian gods. See the Enuma Elish. The order of created objects in Genesis 1 follows the order of the appearance of gods in the Enuma Elish.
3. Because everthing is created by Yahweh, magic does not exist.
4. There are no animal "spirits" as in animism, because all animals are creations of Yahweh.
5. Humans are created for their own sakes. They are
not the playthings and servants of the Babylonian gods as depicted in the Enuma Elish.
6. Humans have "dominion" over the earth. That is, whatever they decide to do to and with the earth, Yahweh will back ("in his image") as tho Yahweh were doing it.
7. An (un)necessary justification for the Sabbath.
There is also some ancient numerological and theological significance in the numerology of Genesis 1. Creation is split into two 3 day periods and each day has 3 major creation events. The number 3 was thought to be significant at the time.