Like all holidays, Pesach focuses our attention on something we should remember every day. In particular, the first of the Six Remembrances is as follows:
(3) You shall not eat anything leavened with it; for seven days thereafter*thereafter Lit. “upon it.” you shall eat unleavened bread, bread of distress—for you departed from the land of Egypt hurriedly—so that you may remember the day of your departure from the land of Egypt as long as you live.
Where do we see a reference to "the day" of leaving Egypt?
(מא) וַיְהִ֗י מִקֵּץ֙ שְׁלֹשִׁ֣ים שָׁנָ֔ה וְאַרְבַּ֥ע מֵא֖וֹת שָׁנָ֑ה וַיְהִ֗י בְּעֶ֙צֶם֙ הַיּ֣וֹם הַזֶּ֔ה יָ֥צְא֛וּ כׇּל־צִבְא֥וֹת ה' מֵאֶ֥רֶץ מִצְרָֽיִם׃
(41) at the end of the four hundred and thirtieth year, to the very day, all the ranks of 'ה departed from the land of Egypt.
Rashi comments on every part of this verse except the expression "כׇּל־צִבְא֥וֹת ה'" although this is the first appearance of this expression in the Tanakh. Perhaps this is because on the level of pshat it needs no explanation, and yet in a sense this "כׇּל־צִבְא֥וֹת ה'" is what is new on this day. What, therefore, does it mean?
(ח) וַיַּ֗עַשׂ אֵ֚ת הַכִּיּ֣וֹר נְחֹ֔שֶׁת וְאֵ֖ת כַּנּ֣וֹ נְחֹ֑שֶׁת בְּמַרְאֹת֙ הַצֹּ֣בְאֹ֔ת אֲשֶׁ֣ר צָֽבְא֔וּ פֶּ֖תַח אֹ֥הֶל מוֹעֵֽד׃ {ס}
(8) He made the laver of copper and its stand of copper, from the mirrors of the women who congregated (בְּמַרְאֹת֙ הַצֹּ֣בְאֹ֔ת) at the entrance of the Tent of Meeting.
(1) במראת הצבאת OF THE MIRRORS OF THE WOMEN CROWDING — The Israelitish women possessed mirrors of copper into which they used to look when they adorned themselves. Even these did they not hesitate to bring as a contribution towards the Tabernacle. Now Moses was about to reject them since they were made to pander to their vanity, but the Holy One, blessed be He, said to him, “Accept them; these are dearer to Me than all the other contributions, because through them the women reared those huge hosts in Egypt!” For when their husbands were tired through the crushing labour they used to bring them food and drink and induced them to eat. Then they would take the mirrors, and each gazed at herself in her mirror together with her husband, saying endearingly to him, “See, I am handsomer than you!” Thus they awakened their husbands’ affection and subsequently became the mothers of many children, at it is said, (Song 8:5) “I awakened thy love under the apple-tree”, (referring to the fields where the men worked). This is what it refers to when it states, מראות הצבאת “the mirrors of the women who reared the hosts (צבאות)” (Midrash Tanchuma, Pekudei 9). And it was for this reason that the laver was made of them (the mirrors) — because it served the purpose of promoting peace between man and wife viz., by giving of its waters to be drunk by a woman whose husband had shown himself jealous of her and who nevertheless had associated with another (cf. Numbers ch. V) thus affording her an opportunity to prove her innocence (cf. Sotah 15b). You may know that the מראות mentioned in the text were really mirrors (and that the word does not mean visions, or appearance, etc.), for it is said, (v. 29) “And the copper of the wave-offering was seventy talents etc. … and therewith he made [the sockets etc.]” — the laver, however, and its base are not mentioned there amongst the articles made from that copper; hence you may learn that the copper of which the laver was made was not a part of the copper of the weave-offering, which is the only copper mentioned as having been contributed by the people. Thus did R. Tanchuma 2:11:9 explain the term מראת הצבאת. And so does Onkelos also render it: במחזית נשיא, and this first word is the Targum translation of מראות, in the sense of mireors in old French, for we find that for the word (Isaiah 3:23) “And the גליונים”, which are mirrors, we have in the Targum the same word מחזיתא. (2) אשר צבאו [THE WOMEN] WHO CAME IN CROWDS to bring their contribution.
דָּרֵשׁ רַב עַוִּירָא: בִּשְׂכַר נָשִׁים צִדְקָנִיּוֹת שֶׁהָיוּ בְּאוֹתוֹ הַדּוֹר נִגְאֲלוּ יִשְׂרָאֵל מִמִּצְרַיִם....
§ Rav Avira taught: In the merit of the righteous women that were in that generation, the Jewish people were redeemed from Egypt. ...
It was only because the women believed in a Jewish future and were ready to act in accordance with that belief by having children under the most brutal circumstances that the jews merited that future.
If the above connection to childbirth is not enough, consider that Chana is credited as being the first to use the inverse expression "L-rd of hosts" (1 Sam 1:11) in her prayer for a child (Pesikta Rabbati).
The association of the name Atzereth with the last day of Pesach and Succoth allows for the translation "Concluding Festival" and it is in this sense that the rabbis refer to Shavuoth as Atzereth shel Pesach the Concluding Festival of Passover. By this title they indicate not merely that Shavuoth marks the end of the grain harvests which began at Passover with the barley, but that the freedom gained by Israel at the Exodus was not really complete until they stood at Sinai...
...אָמְרוּ לְפָנָיו רִבּוֹנוֹ שֶׁל עוֹלָם נְבִיאֵינוּ עֲרֵבִין לָנוּ. אָמַר לָהֶם יֵשׁ לִי עֲלֵיהֶם, שֶׁנֶּאֱמַר (ירמיה ב, ח): וְהָרֹעִים פָּשְׁעוּ בִי וגו', וּכְתִיב (יחזקאל יג, ד): כְּשֻׁעָלִים בָּחֳרָבוֹת נְבִיאֶיךָ יִשְׂרָאֵל הָיוּ, אֶלָּא הָבִיאוּ לִי עֲרֵבִים טוֹבִים וְאֶתְּנֶנָּהּ לָכֶם, אָמְרוּ הֲרֵי בָּנֵינוּ עוֹרְבִים אוֹתָנוּ. אָמַר הַקָּדוֹשׁ בָּרוּךְ הוּא הָא וַדַּאי עֲרֵבִים טוֹבִים, עַל יְדֵיהֶם אֶתְּנֶנָּהּ לָכֶם, הֲדָא הוּא דִכְתִיב (תהלים ח, ג): מִפִּי עוֹלְלִים וְיֹנְקִים יִסַּדְתָּ עֹז, וְאֵין עֹז אֶלָּא תּוֹרָה, שֶׁנֶּאֱמַר (תהלים כט, יא):
...They said before Him: ‘Master of the universe, our prophets will be guarantors for us.’ He said to them: ‘I have [claims] against them, as it is stated: “And the shepherds were disloyal to me [and the prophets prophesied to the Baal]” (Jeremiah 2:8). And it is written: “Like foxes among the ruins, so are your prophets, Israel” (Ezekiel 13:4). Rather, bring me effective guarantors and I will give it to you.’ They said: ‘Our children are guaranteeing for us.’ The Holy One blessed be He said: ‘They are certainly good guarantors, I will give it to you on their account.’ That is what is written: “From the mouths of infants and sucklings You founded strength” (Psalms 8:3), and strength means only Torah, as it is stated: “The Lord will give strength to His people (Psalms 29:11).
We see that the children which the women set up at Pesach are also the guarantors at Shavuot.
The Gemara cites additional homiletic interpretations on the topic of the revelation at Sinai. The Torah says, “And Moses brought forth the people out of the camp to meet God; and they stood at the lowermost part of the mount” (Exodus 19:17). Rabbi Avdimi bar Ḥama bar Ḥasa said: the Jewish people actually stood beneath the mountain, and the verse teaches that the Holy One, Blessed be He, overturned the mountain above the Jews like a tub, and said to them: If you accept the Torah, excellent, and if not, there will be your burial. Rav Aḥa bar Ya’akov said: From here there is a substantial caveat to the obligation to fulfill the Torah. The Jewish people can claim that they were coerced into accepting the Torah, and it is therefore not binding. Rava said: Even so, they again accepted it willingly in the time of Ahasuerus, as it is written: “The Jews ordained, and took upon them, and upon their seed, and upon all such as joined themselves unto them” (Esther 9:27), and he taught: The Jews ordained what they had already taken upon themselves through coercion at Sinai.
What began on Shavuot was only completed on Purim.
(ד) לְאַחַר שֶׁעָשָׂה הָעֵץ, הָלַךְ אֵצֶל מָרְדֳּכַי וּמְצָאוֹ שֶׁהָיָה יוֹשֵׁב בְּבֵית הַמִּדְרָשׁ וְהַתִּינוֹקוֹת יוֹשְׁבִים לְפָנָיו וְשַׂקִּים בְּמָתְנֵיהֶם וְעוֹסְקִים בַּתּוֹרָה, וְהָיוּ צוֹעֲקִים וּבוֹכִים, וּמָנָה אוֹתָם וּמָצָא שָׁם [שנים עשר] [שנים ועשרים אלף] תִּינוֹקוֹת, הִשְׁלִיךְ עֲלֵיהֶם שַׁלְשְׁלָאוֹת שֶׁל בַּרְזֶל וְהִפְקִיד עֲלֵיהֶם שׁוֹמְרִים, וְאָמַר לְמָחָר אֶהֱרֹג אֵלּוּ הַתִּינוֹקוֹת תְּחִלָּה, וְאַחַר כָּךְ אֶתְלֶה אֶת מָרְדֳּכָי. וְהָיוּ אִמּוֹתֵיהֶם מְבִיאוֹת לָהֶם לֶחֶם וּמַיִם וְאוֹמְרוֹת לָהֶם בָּנֵינוּ אִכְלוּ וּשְׁתוּ קֹדֶם שֶׁתָּמוּתוּ לְמָחָר וְאַל תָּמוּתוּ בָּרָעָב, מִיָּד הָיוּ מַנִּיחִין יְדֵיהֶם עַל סִפְרֵיהֶם וְנִשְׁבָּעִים בְּחַיֵּי מָרְדֳּכַי רַבֵּנוּ לֹא נֹאכַל וְלֹא נִשְׁתֶּה, אֶלָּא מִתּוֹךְ תַּעֲנִיתֵנוּ נָמוּת, גָּעוּ כֻּלָּם בִּבְכִיָּה עַד שֶׁעָלְתָה שַׁוְעָתָם לַמָּרוֹם וְשָׁמַע הַקָּדוֹשׁ בָּרוּךְ הוּא קוֹל בְּכִיָּתָם כְּבִשְׁתֵּי שָׁעוֹת בַּלַּיְלָה, בְּאוֹתָהּ שָׁעָה נִתְגַּלְגְּלוּ רַחֲמָיו שֶׁל הַקָּדוֹשׁ בָּרוּךְ הוּא וְעָמַד מִכִּסֵּא דִּין וְיָשַׁב בְּכִסֵּא רַחֲמִים, וְאָמַר מַה קּוֹל גָּדוֹל הַזֶּה שֶׁאֲנִי שׁוֹמֵעַ כִּגְדָיִים וּטְלָאִים, עָמַד משֶׁה רַבֵּנוּ לִפְנֵי הַקָּדוֹשׁ בָּרוּךְ הוּא וְאָמַר, רִבּוֹנוֹ שֶׁל עוֹלָם לֹא גְדָיִים וְלֹא טְלָאִים הֵם אֶלָּא קְטַנֵּי עַמְךָ שֶׁהֵם שְׁרוּיִים בְּתַעֲנִית הַיּוֹם שְׁלשָׁה יָמִים וּשְׁלשָׁה לֵילוֹת, וּלְמָחָר רוֹצֶה הָאוֹיֵב לְשָׁחֲטָם כִּגְדָיִים וּטְלָאִים. בְּאוֹתָהּ שָׁעָה נָטַל הַקָּדוֹשׁ בָּרוּךְ הוּא אוֹתָן אִגְרוֹת שֶׁגָּזַר עֲלֵיהֶם שֶׁהָיוּ חֲתוּמוֹת בְּחוֹתָם שֶׁל טִיט, וּקְרָעָם, וְהִפִּיל עַל אֲחַשְׁוֵרוֹשׁ בֶּהָלָה בְּאוֹתוֹ לַיְלָה, הֲדָא הוּא דִכְתִיב: בַּלַּיְלָה הַהוּא וגו'.
(4) After he erected the gibbet, he went to Mordekhai and found that he was sitting in the study hall with the children sitting before him, with sackcloth on their waists, engaging in the study of Torah, and they were screaming and weeping. He counted them and found there twenty-two thousand children. He cast iron chains on them and deployed guards over them. He said: ‘Tomorrow, I will kill these children first and then I will hang Mordekhai.’ Their mothers were bringing them food and water and saying to them: ‘Our children, eat and drink before you die and don’t die hungry.’ Immediately, they placed their hands on their books and took an oath: ‘By the life of Mordekhai our master, we will not eat and drink, but will die while fasting.’ All of them began weeping loudly until their cries reached the heavens. The Holy One blessed be He heard the sound of their weeping approximately two hours into the night.
At that moment, the compassion of the Holy One blessed be He was aroused, and He stood up from His throne of justice and sat down on His throne of mercy, and said: ‘What is that loud sound I hear that sounds like goats and lambs?’ Moses our master stood before the Holy One blessed be He and said: ‘Master of the universe, they are neither goats nor lambs, but rather the children of Your people, who are fasting today [and have already been fasting for] three days and three nights, and tomorrow their enemy seeks to slaughter them like goats and lambs.’ At that moment, the Holy One blessed be He took those letters that He had decreed against them that were sealed with mortar seals and He ripped them.4See Esther Rabba 7:14. He brought fear upon Aḥashverosh that night; that is what is written: “On that night [sleep deserted the king, and he ordered the book of records, the annals to be brought; and it was read to the king] (Esther 6:1).
The Jews were saved on Purim only in the merit of Mordechai gathering the children together. On high it was Moses who, perhaps likening the children to the Paschal Offering demands justice from G-d thus bringing the matter of redemption full circle.
My father proclaimed at a farbrengen: Just as wearing tefillin every day is a Mitzva commanded by the Torah to every individual regardless of his standing in Torah, whether deeply learned or simple, so too is it an absolute duty for every person to spend a half hour every day thinking about the Torah-education of children, and to do everything in his power - and beyond his power - to inspire children to follow the path along which they are being guided.