וירא אלוהים את האור כי טוב, "God saw the light that it was good, etc.⁠" According to the plain meaning of this verse, the word וירא, "He saw,⁠" means that God approved of what He saw and decreed that it should endure. In Talmudic Hebrew we find the word ראה, "he saw,⁠" as a sign of approval such as when the Talmud says in Ketuvot 109 רואה אני את דברי אדמון, "I approve of the words of the sage called Admon.⁠" You will find that these words are attributed to God on every day of the creation, i.e. He surveyed what had developed and approved of it. God decreed permanence for each of the phenomena or creatures which had come into existence. If God's goodwill would depart from these phenomena even briefly they would turn back into nothingness. This is why He sealed the entire creative process (Genesis 1,31) with the words והנה טוב מאד "and here it was very good.⁠" These words expressed God's desire that the universe would endure.
As to the additional words ואת האור in our verse instead of merely the words וירא אלוהים כי טוב, they were needed as otherwise we would have thought that the words כי טוב referred to the creation of heaven and earth instead of to the creation of light. God did not yet decree that heaven and earth should endure seeing they were incomplete and only on the second day did the separation of heaven and earth occur when the רקיע,⁠"firmament" was created to divide between them. Finally, on the third day, the upper waters and the waters in the lower regions were separated. This completed the process of creating heaven and earth. At that point God decreed that they should endure and He said: "it was good.⁠"

Looking at our verse from an homiletical point of view, the question is: what did God see now, i.e. something new, which He had not been aware of previously? Answer: He saw that this light was not fit for the wicked in this world to make use of; as a result He decided to hide it for future use by the righteous in the world to come .

A kabbalistic approach to our verse yields the following insight. The words את האור were meant to include something that Rabbi Akiva achieved when he "descended into the "Pardes,⁠" regions of enquiry into the mysteries of the universe. He was the only person to emerge intellectually unharmed and physically intact from such studies as we know from Shir Hashirim Rabbah 1,28 as well as Chagigah 15. It is also possible that these words were meant to convey that the souls were created simultaneously with this light. This idea is hinted at in Job 38,19: איזה הדרך ישכן אור, "which path leads to where light dwells?⁠" And it says also (verse 21 there) "Surely You know for you were born then, and the number of your years is many.⁠" [Nachmanides explains these verses in the manner our author understands them. Rabbi Chavel.]

ויבדל אלוהים בין האור ובין החשך God separated between the light and the darkness.⁠" According to the plain meaning, the word חשך here refers to the absence of light. It is not the same as the "darkness" which we discussed earlier in connection with the words "the darkness was on the face of the deep (1,2).⁠" We had described that particular brand of darkness as "fire.⁠"
The Torah does not mention the words כי טוב "that it was good,⁠" in connection with the second day. On the third day however, when God completed what He had done with the water the Torah mentions the word טוב, "good" twice; the first time the word refers to completion of the creative directives associated with the waters, the second time to express God's satisfaction with the progress achieved on that day itself.
My question concerning this is: Why should the fact that the directives concerning the water on earth had not yet been completed cause the Torah omit to mention that what had been achieved was "good?⁠" Seeing that the skies, as well as the angels had been completed on that day the Torah should have described this as "good?⁠" God should have decreed that these phenomena should endure, just as He had in connection with the accomplishments on the first day! None of these achievements appear inferior to the ones which were deemed as deserving to endure as soon as they had been created! I believe that the absence of the word טוב at this juncture is potent proof for the argument that this "lower" terrestrial universe represents God's main purpose in creating the universe. As long as the Jewish people perform the will of God, observe what is written in the Torah, our domain is the principal arena of the universe Even though God had completed creation of the angels already on the second day, that day was not distinguished by the description "good" being applied to it. Nothing in the celestial regions qualified for permanence until the waters in the terrestrial world had been separated from the dry land when God gave that directive on the third day and said: יקוו המים מתחת השמים אל מקום אחד ותראה היבשה "let the waters which are below the heaven congregate in one area so that the dry land becomes visible.⁠" Once this directive had been carried out, the heaven, i.e. the celestial regions, qualified for permanence. At that point the Torah saw fit to describe the creation of the celestial regions as being "good.⁠"
Our sages summarise their commentary on this paragraph in Bereshit Rabbah 5,7 as follows: "seeing the work involving the waters had not yet been completed, because it had not been completed in the terrestrial regions, the Torah did not want to mention that the creation of the celestial regions was "good.⁠" We see from here that the terrestrial part of the universe is the principal part of existence. Perhaps this is the reason that the dry land was called ארץ, seeing it was this region which completes carrying out God's will and His intention when creating a physical existence, His intention when creating a physical existence, מציאות . [I believe that what is meant here is that the last two letters in the word ארץ are an abbreviation of the word רצון, pointing to God's will, whereas the first letter א may allude to God as the אחד, the One and Only Unique One. Ed.] The author attributes his conclusions by pointing to Maleachi 3,12 who speaks about ארץ חפץ, the implication being that "earth performs the will of the Lord.⁠"
We also find in connection with the fourth day in the paragraph "let there be luminaries in the sky of the heaven,⁠" that the Torah clearly hints that that the luminaries were created only for the sake of being useful in this terrestrial world. This is what is meant by the words (1,15) להאיר על הארץ, "to provide light on earth.⁠" This proves that the creatures of the celestial regions, though great and mighty in stature, nonetheless have been created only for the sake of the creatures in the "lower" regions of the universe. I have further proof from the mouth of Moses himself who has said in (Deut. 10,14) הן לה' אלוהיך השמים ושמי השמים "indeed the heavens as well as the heaven of the heavens belong to the Lord.⁠" The fact that Moses mentioned the "heaven" of our lower regions, i.e. the sky first, indicates that he considered it as more important to God than the celestial "heaven.⁠" All these comments by our sages are homiletical comment in Sanhedrin 93, where they phrased is as: "the righteous are greater than the ministering angels of God.⁠"

Another homiletical comment is based on the sages there asking: "why was the word טוב omitted on the report of the second day? Because on this day the גהנם, 'purgatory' was created.⁠" We surmise this from Isaiah 30,33 כי ערוך מאתמול תפתה, "for Tophet has long been ready for him, having been created yesterday.⁠" This day was called אתמול, "yesterday,⁠" as it was a day which had a "yesterday" but no "day before yesterday.⁠" Another reason cited by our sages (Bereshit Rabbah 4,5) for the absence of the word "good" on the second day is that מחלוקת, strife, was created on that day. This is what is meant by the words(1,6) ויהי מבדיל בין מים למים, "and it will form a divide between waters and waters.⁠" Rabbi Tivyomi commented on this: "if even a divisiveness which served the purpose of the Lord did not deserve to be described as "good,⁠" how much more so must divisiveness which does not serve the purpose of the Lord but is designed to frustrate His works be hateful?⁠"
From a conceptual point of view we may see that the the very number "second" implies that something has become different, other than the unity implied in the word "one.⁠" It is the source of all division and otherness. As far as the sages saying that both purgatory and strife were created on that same day, they meant to tell us that whoever is guilty of causing strife will ultimately wind up in purgatory. Seeing that both strife and purgatory were created on that day, we may view that day as one that causes damage. To implant this in our consciousness the sages (Zohar on Eykev 271) decreed that one must not commence new projects on Mondays. Not only this, but we are told in Pesachim 109 not to eat זוגות "food in "twos", i.e. two dishes, as this is a health hazard for people. This prohibition is based on the fact that the first "Monday", second day, was not blessed with the description "good.⁠" It all goes back to the fact that the divisiveness introduced into the universe on that day was the first of its kind.
Starting with this divisiveness, other disagreements ensued, such as earth not complying with the will of God. On the third day (1,11-12) when God directed that earth should produce עץ פרי עושה פרי "fruit bearing trees which are themselves edible,⁠" all that earth produced were עץ עושה פרי, "fruit-bearing trees.⁠" The trunks earth produced were not edible. On the fourth day, the day when the luminaries were hung in the sky, the two large luminaries soon turned into a larger one and a smaller one. Our sages in Chulin 60 relate that there was an argument between the moon and God concerning the sun's superior status. God had to intervene and ask the moon to downsize. On the fifth day God had to "salt away" the female of the Leviathan as explained by our sages in Baba Batra 74. Acccording to the Talmud God castrated the male of that species while killing the female. and preserving its flesh (salting it away) for consumption by the righteous in the distant future. On the sixth day, the day the first man and woman were created, they sinned, causing further divisiveness and resulting in their banishment from גן עדן. We observe that divisions were manifest on every single one of the days following the second day when such divisiveness first appeared.