In theology, a distinction is made between “first creation” and “second creation” (creatio prima/secunda). In the “first creation”, God created the whole universe and his heavens out of nothing; this is described in Gen. 1:1.* The “second creation” begins with the First Day in Gen. 1:3. Herman Bavinck writes in his Reformed Dogmatics (§2.269):
“Genesis gives no other impression but that the creation of heaven and earth in verse 1, and the unformed state of the earth in verse 2, precedes the First Day. … The work of the First Day did not consist in the creation of heaven and earth, not in the maintenance of the unformed state, but in the creation of the light and the separation of light and darkness.”
The Bible puts most emphasis on the “second creation”, which has to do with the development and organization of our direct environment. The reasoning in the fourth commandment (Ex. 20:11) is that “in six days God made the heavens, the earth, the sea, and all that is in them.” The mentioning of the sea makes clear that we must think here of the three levels of the biosphere: sky, land, sea. The most important things for us to know are not the details about origin of galaxies and rocks, but about the part of the world in which God provides all we need to support our lives.
The creation of light on the First Day is described as an immediate creation: God spoke, and it came into being. But the creation of sky, sea, and land is more indirect. God used what he had created before and made separation: water above, water below, and places where the water receded so that people and animals could live there.
The creation of plants was also indirect: God gave the earth the potential to bring forth abundant life: “The earth brought forth vegetation.” (Gen. 1:12) In the same way, the animals in sky and sea are closely associated to the realm in which they live. Ultimately, even the man was formed from the dust on which he would walk. (Gen. 2:7) This careful description shows, on one hand, that there is a kinship between living creatures and the world in which they live: plants are an essential part of the soil, people belong to the earth. On the other hand, plants, animals, and people did not grow out of soil, water, and air through a natural process; only a deliberate, supernatural word of creation could produce that life. The matter of which we are made, the biosphere in which we live, and the form and functionality our bodies are all the result of God’s mighty Word.