31.’ And G-d saw every thing that He had made, and, behold, it was very good. And there was evening and there was morning, The Sixth Day- וַיַּרְא אֱלֹהִים אֶת כָּל אֲשֶׁר עָשָׂה וְהִנֵּה טוֹב מְאֹד וַיְהִי עֶרֶב וַיְהִי בֹקֶר יוֹם הַשִּׁשִּׁי (3065=14=8 or 4185=18 counting final Mems as 600).

Rashi comments here that the prefix “The” is added to the Sixth Day- הַשִּׁשִּׁי (at the end of the period of Creation) to teach us that Creation is brought into existence for the condition that Israel accepts upon themselves the Five Books of the Torah.The gematria of the letter Heh- ה' is 5 (Tanchuma 1). Alternatively, all of the components of Creation were in a state of suspension until the Sixth Day of Sivan 2448 (Shabbat) the Festival of Shavuoth/Atzeret when Israel received the Torah on Mount Sinai (Shabbat 88.a). 

In my opinion these two comments can be amalgamated and understood as follows:

The ultimate purpose of Creation, the combination of the Metaphysical (8) and the Physical (1) Worlds, “The World of the Heavens” and “The World of the Earth” is to be revealed at the end of “THE” Sixth Day when Israel returns to Hashem in repentance and accepts upon itself to uphold the Torah. The Metaphysical World is in a state of suspension to be joined to the physical world and there will be a New Beginning. This will be the Shabbat that is all good-שבת שכולו טוב. Thus we can comprehend why the entire Creation Process up until this verse is written in thefuture tense. There is something bigger and better yet to come; the veil of darkness shall be removed from the physical world and the Hidden Light of the Metaphysical World will be revealed at the time of Israel’s Final Redemption. This will be on Shemini Atzeret, the Eighth Day of Shavuoth, Pesaqch L'Hashem!

Thus it is written “The Sixth Day”- יוֹם הַשִּׁשִּׁי and not “a Sixth Day”- יוֹם שִּׁשִּׁי. It is a promise of the future, The Sixth Day before the entrance of “The Seventh Day”- יּוֹם הַשְּׁבִיעִי “that has Shabbat IN IT”- כִּי בוֹ שָׁבַת as we read in the following verse.

The Sixth Day is connected to The Seventh Day as is shown by the following gematria:

The Sixth Day-The Seventh Day

יוֹם הַשִּׁשִּׁי-יּוֹם הַשְּׁבִיעִי

1124=8

This is why on the Shabbat eve we begin the Sanctification “Kiddush” of Shabbat with the words

And there was evening and there was morning, The Sixth Day

וַיְהִי עֶרֶב וַיְהִי בֹקֶר יוֹם הַשִּׁשִּׁי

1307+6 words=1313=8

Resurrection of the Dead

תחית המתים

1313=8

This is why Hashem called this day “Very Good”- טוֹב מְאֹדbecause the ultimate purpose of Creation was about to come into fruition and Hashem could finally rest on the Shabbat, the Eighth Day.

The words “Very Good” are a precursor to the combination of the Physical and Metaphysical Worlds as is shown by their gematria:

Very Good

טוֹב מְאֹד

62=8

+2 words=64=10=1