Then the LORD said to Moses, “Hold out your hand toward the sky that there may be darkness upon the land of Egypt, a darkness that can be touched.”
נְטֵה יָדְךָ עַל הַשָּׁמַיִם וִיהִי חֹשֶׁךְ. מֵהֵיכָן הָיָה אוֹתוֹ הַחֹשֶׁךְ? רַבִּי יְהוּדָה וְרַבִּי נְחֶמְיָה. רַבִּי יְהוּדָה אוֹמֵר: מֵחֹשֶׁךְ שֶׁל מַעְלָה
Stretch out thy hand toward heaven, that there may be darkness (Exod. 10:21). Where did the darkness come from? ..R. Judah held: It descended from the darkness of the upper regions
He made darkness His screen;
dark thunderheads, dense clouds of the sky
were His pavilion round about Him.
Let us first start by looking at a teaching from the Holy Ohr HaChaim
So Moses held out his rod toward the sky, and the LORD sent thunder and hail, and fire streamed down to the ground, as the LORD rained down hail upon the land of Egypt.
And in regards to the verse that says 'But all the children of Israel there was light in their homes' (verse below) the Chizkuni asks why is the location of the plague not effecting the Israelites not mentioned here like it is in all the other plagues, as in all the other plagues the Torah says in the land of Goshen (which is where the Israelites dwelled) - rather it specifies that the location the Israelites weren't effected was specifically in their house. The intention of the question here is why is the home of the Israelites mentioned as where the plague wasn't, when all the other plagues used the city of the Israelites to mention the location of the lack of plague.
People could not see one another, and for three days no one could get up from where he was; but all the Israelites enjoyed light in their dwellings.
Rather, the purpose of the exile and the redemption of Israel in Egypt was that all the inhabitants of the world became aware that there was a 'ruler over the palace' (A Lord that rules over the world). We know this as its written -
Nevertheless I have spared you for this purpose: in order to show you My power, and in order that My fame may resound throughout the world.
And behold, its written in the book of Kohelet by King Solomon
Whereas a fool walks in darkness.
But I also realized that the same fate awaits them both.
And later on in this Talmud it teaches -
ואיבעית אימא לעולם הבא כדרשב"ל דאמר רבי שמעון בן לקיש אין גיהנם לעתיד לבא אלא הקדוש ברוך הוא מוציא חמה מנרתיקה ומקדיר רשעים נידונין בה וצדיקים מתרפאין בה רשעים נידונין
..Rabbi Shimon ben Lakish says: There is no Hell in the World-to-Come. Rather, the Holy One, Blessed be He, will remove the sun from its sheath, where it is situated during these times, and heats that world with it. The wicked will be punished by it and consumed by the heat, but the righteous will be healed by it..
But for you who revere My name a sun of victory shall rise to bring healing. You shall go forth and stamp like stall-fed calves.
רַבִּי שִׁמְעוֹן בֶּן יוֹחַי אוֹמֵר אֶבֶן טוֹבָה הָיְתָה תְּלוּיָה בְּצַוָּארוֹ שֶׁל אַבְרָהָם אָבִינוּ שֶׁכׇּל חוֹלֶה הָרוֹאֶה אוֹתוֹ מִיָּד מִתְרַפֵּא וּבְשָׁעָה שֶׁנִּפְטַר אַבְרָהָם אָבִינוּ מִן הָעוֹלָם תְּלָאָהּ הַקָּדוֹשׁ בָּרוּךְ הוּא בְּגַלְגַּל חַמָּה
Rabbi Shimon ben Yoḥai says: A precious stone hung around the neck of Abraham our forefather; any sick person who looked at it would immediately be healed. When Abraham our forefather died, the Holy One, Blessed be He, hung this stone from the sphere of the sun..
And behold, when humanity discusses things of the intellect and gaining clarity, verbiage of light is always used (A lightbulb went off in my mind). And in matters of things that don't make sense to people or where there is a lack of clarity, verbiage of dark is always used (My mind is cloudy). Just like in a dark room one cannot see anything, so too, something that the mind cannot comprehend, that thing will be hidden from them and not able to be 'seen'.
And this is exact the intention of the following verse -
Knows what is in the darkness,
And light dwells with Him.
And if we look into the Holy writings of Israel, we can see the main difference between the nations of the world and the Children of Israel. Regarding Israel, they believe something that they cannot see or grasp, and because of that they are able to understand and perceive metaphysical realities (beyond the laws of nature), which matters of that category cannot be grasped by our rationale mind. This however is not the case with the nations of the world, in which case they only believe in what their eyes can see, and they don't believe that the Holy One Blessed be He created and oversees all that was created, and He alone does, did, and will act upon all of creation. And that He oversees the world personally, and for the nations, it's difficult for them to understand something well beyond what the rationale mind can comprehend.
And behold in the future to come, a great light, the hidden light, that was saved for the righteous will be released/revealed.
Rabbi Elazar said: The light that the Holy One, Blessed be He, created on the first day was not that of the sun but a different kind of light, through which man could observe from one end of the world to the other. But when the Holy One, Blessed be He, looked upon the generation of the Flood and the generation of the Dispersion and saw that their ways were corrupt and that they might misuse this light for evil, He arose and concealed it from them, as it is stated: “And from the wicked their light is withheld” (Job 38:15). And for whom did He conceal it? For the righteous people in the future..
And regarding what we learned above about the time when the Holy One Blessed be He shines the sun on the nations of world (during Sukkot) from its peak heat in Tamuz. The explanation here is that this peak sun is a reference to the great light of the future that is destined to shine down on the world, and when that happens the nations of the world won't be able to deal with such a light, since they cannot comprehend what is above what is rationale and material, and then everyone will leave their Sukkah, which means that people will start to deny the Blessed HaShem and throw off the burden of His Kingship. Since they don't believe in anything that they cannot grasp and comprehend with their logic and understanding.
And this is also the explanation from what we said above regarding when HaShem removed the sun from its sheath, and the wicked get punished by it, and the righteous heal from it, as we had the verse from Malachi "But for you who revere My name a sun of victory shall rise to bring healing. You shall go forth and stamp like stall-fed calves."
And this settles our question. That even a fool, which we can translate as someone full of sin, as we see from the sages -
Reish Lakish says: A man commits a transgression only if a spirit of folly [shetut] enters him..
