God couldn't finish what he had set out to accomplish on the second day? So God is not all that potent is he?
Unless the bible is talking about something slightly different, the gestation period is the growing of the fetus in the womb of the mother.
On the first day it was the the mother (heaven) and father (earth) having sex, creating a baby,
Not for nothing it says that 'the earth was wondering and bewildered'( תֹהוּ וָבֹהו
, not 'void and without form'. that is the English translation which is misleading.
And why was the earth the only one to be תֹהוּ וָבֹהוּ why wasn't the Heaven in the same state?
Think for yourself and you will see the act.
Inside the cave of the woman נְקֵבָה the port, the male, the ship, off load its cargo.
And there was light.
Light - אוֹר Or, = All spin and vibrate.
When the sperm penetrates the egg inside the woman's cave, a 'big bang', an explosion occurs.
Life begins.
But on the following 9 months period there is no result, it's a waiting period, waiting for the baby to come out.
That is the reason the Elohim (God) did not see that it was good, he was waiting, nothing to do but wait.
6. Let there be a firmament in the midst of the waters, and let it divide the waters from the waters.
That is the membrane inside the womb, where the baby is formed, separating the waters above and below.
Maxim of law: 'The land and everything on the land is land'.
When baby emerges from the womb, born on the water, there is a separation of 'Land' (baby) and water (mother), but not entirely, there is still a period of suckling, wet nursing, it takes a bit of time and the baby grows to be a 'Child'. (Child under land laws=still born-dead-corpus)
Second part of the 'third day':
When we reach around 9 years old the Hormone system begins to appear in the form of grass and trees on our bodies, the land, and the fruit (the concept of YHVH) develops and matures.
According to the Talmud a 9 year old can testify in court, why? Because YHVH, the 'fruit', resides in him.