Day 3 of the creation week was unique, and a turning point in the creation week. When God first made the “earth” and heaven, the earth was tohu-v-bohu, formless and empty, and also dark. Over the course of the creation week, God corrected these imperfections of the original earth.
First He calls light into being to chase away the darkness. Then He sets the light and dark into a pattern, structuring the world temporally. By the end of Day 1, the world is no longer dark, at least not all the time; and it is no longer completely formless. It has a shape and a pattern of movement, from evening to morning, evening to morning.
Days 2-3 are mostly about structure. Creation is a science of division; it is also hydraulics. God divides the waters, moving some up and inserting a firmament between to keep them separate. There’s a heavenly sea above, and an earthly sea below. Day 3 is another act of division, another hydraulics project, as God separates the waters below so that the dry land appears. By Day 3, we have a structured universe—firmament above, earth beneath, waters under the earth, all moving through a temporal structure of evening and morning. Time and space have been given shape. The world is no longer tohu.
It is, however, bohu, empty. And this brings us to the uniqueness of Day 3. It is the first day on which God engages in two separate acts of creation, when He speaks twice. He speaks to the waters to gather them in one place so that dry land can appear; then He speaks again to the earth and tells it to sprout with vegetation.
Not only does God speak twice, but the second time He speaks, He tells the creation to produce something. He speaks light into being; He says “let there be a firmament” and there is; He says “let the waters . . . be gathered” and they are. But the instruction to the ground is different. For the first time, creation actively participates in its own formation. It can participate only because God the Creator has spoken His creative word to the ground. Apart from that Word, the ground has no power to produce anything at all. But in response to the creative Word, the ground becomes productive. God creates by conferring productivity on creatures; the Creator creates by making created things creative. He is the Creator of all, and yet He creates through what is truly other than Himself.
God’s double speech, and His conferral of productivity on the creation, mark a turning point in the creation week. He has been forming, now He begins filling. Plants are the first items to fill the earth, and from this point on the week is all about filling—filling the firmament with those ruling lights, filling the oceans with teeming fish and the sky with swarms of birds, and the land with swarming things and animals and finally human beings.
There’s another day of multi-speak in the creation week: the sixth day, when God created land animals—beasts and cattle—and also human beings. Again, God speaks to the earth to bring forth living things; then He speaks to command them to be fruitful; then He speaks again, more personally, to declare that He is creating human beings, male and female, in His image and likeness, to rule the rest of creation.
The structure is similar to Day 3, and suggests created analogies between the things created on Days 3 and 6. Plants and human beings both spring from the earth. Plants are fruitful, and human beings are instructed to be fruitful. An earth clothed with a green mantle is the first product of God's double-talk; a world clothed in animal fur and ruled by humans is the product of the second day of double talk.