Genesis 2:4
4 These are the toldoth ha-shamayim and ha-aretz in their being created, in the yom [that the] LORD God made Eretz [no article] and Shamayim [no article]
Eretz and Shamayim, (without the article) were not both created in a single yom in the previous chapter, (which, imo, is still the same passage in the above text).
Shamayim is/are named by Elohim when it/they were created, in Yom Sheni:
Genesis 1:6-8 KJV
6 And God said, Let there be a firmament in the midst of the waters, and let it divide the waters from the waters.
7 And God made the firmament, and divided the waters which were under the firmament from the waters which were above the firmament: and it was so.
8 And God called the firmament Heaven [Shamayim, no article]. And the evening and the morning were the second day [Yom Sheni].
Eretz is named by Elohim when it was created, in Yom Shelishi:
Genesis 1:9-13 KJV
9 And God said, Let the waters under the heaven be gathered together unto one place, and let the dry land appear: and it was so.
10 And God called the dry land Earth; [Eretz, no article] and the gathering together of the waters called he Seas: and God saw that it was good.
11 And God said, Let the earth bring forth grass, the herb yielding seed, and the fruit tree yielding fruit after his kind, whose seed is in itself, upon the earth: and it was so.
12 And the earth brought forth grass, and herb yielding seed after his kind, and the tree yielding fruit, whose seed was in itself, after his kind: and God saw that it was good.
13 And the evening and the morning were the third day [Yom Shelishi].
Thus, because of the statement in Genesis 2:4 quoted above herein, the yamim of creation in the first chapter of Genesis all occur in one yom: the yom wherein Elohim Almighty created Shamayim, Eretz, and all their host.
Right away, in the very beginning, yom has multiple meanings. This is because Yom is Light, just as Elohim says in Genesis 1:5 where He calls the Light, Yom. If therefore Yom is Light then yom, when it is used for an increment of time, can used for any increment of time. If therefore yom can be a day, then yom can surely also be used for an hour: for yom is not any particular increment of time, but is used in a general way for increments of time, for Yom is instead, Light. And this Light is the Light which Elohim Almighty called forth to shine out of the darkness, (Genesis 1:3). The Yom Light is therefore much more important than the greater light, the lesser light, and the stars which were themselves created in Yom Rebii.
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Moreover your commentary regarding Genesis 2:7 fitting only the sixth day is just your opinion. The context surrounding the first creation actually fits much better with the third day of creation. There was not yet any plant of the field in the earth, and there was not yet any herb of the field sprouted up, and immediately after the first man Adam is formed, and given the breath of life, and becomes a living soul, Elohim plants a garden. This fits the third day much better and this pattern shows up in the parables of the Master all over the place, (Matthew 13 is a good place to start looking for this pattern).
Just as Paul says, the first man Adam became a living soul, (and this is Genesis 2:7), and the second man is from the heavens, and the Psalmist agrees that this is Genesis 1:26-28. What is it then? From the very beginning, ha-adam was recreated in the image and likeness of Elohim, and only then is/are he/they named Adam, (and this also is provable by the Hebrew text and the usage of the definite article).