(9) And God said unto Moses: ‘Lo, I come to you in a thick cloud, that the people may hear when I speak with you, and may also believe in you for ever.’ And Moses told the words of the people to God. (10) And God said to Moses: ‘Go to the people, and sanctify them today and tomorrow, and let them wash their garments, (11) and be ready on the third day; for on the third day God will come down in the sight of all the people upon mount Sinai.
ערב שבועות: ישנים שעה אחת או ב' שעות, אחר שעשו צרכי מועד, לפי שבלילה אחר האכילה מתקבצים בבתי כנסיות, כל קהל וקהל בב"ה שלו, ואינם ישנים כל הלילה, וקורין תורה נביאים וכתובים, ומשניות וזהר ודרשות בקראי עד אור הבוקר...
Avraham Galante - Tzfat d.1589 - describing the customs of Tzfat
The evening before Shavuot: they sleep an hour or two, after preparing the needs of the holiday, because on the night after the meal they gather in the synagogues, each community in its synagogue, and don't sleep the whole night. They read Torah, Prophets and Writings, Mishnah, Zohar and Teachings/Sermons until the light of morning...
How Coffee Paved the Way for Mystical Night Vigils
[B]oth these study vigils [on the eve of Hoshanah Rabbah and Shavuot] began to spread through the Ottoman empire during the 16th century, the same century in which coffee first arrived, changing the possibilities, both sacred and profane, of nightlife in such cities as Cairo, Damascus, and even Safed, [the capital of kabbalah at the time]...
Why stay awake? What good comes from a Torah All-Nighter?
Be Ready: Perhaps a person shouldn't sleep on them at night, because they will hear the voice of God in the morning, like the way of the Kohen Gadol on Yom Kippur.
דע שכל מי שבלילה זה לא ישן כלל ועיקר והיה עוסק בתורה — מובטח לו שישלים שנתו ולא יארע לו שום נזק
R. Chaim Vital - Shaar HaKavanot / Shulchan Aruch HaArizal
Know - that anyone who doesn't sleep at all on this night, and more importantly engages in Torah - it's guaranteed that he will live out the year and no damage will befall him.
This all sounds great. But when given the chance to hear God's voice at Sinai, how did the Israelites react?
(15) All the people witnessed the thunder and lightning, the blare of the horn and the mountain smoking; and when the people saw it, they fell back and stood at a distance. (16) “You speak to us,” they said to Moses, “and we will obey; but let not God speak to us, lest we die.”
בּוֹא וּרְאֵה הֵיאַךְ הַקּוֹל יוֹצֵא, אֵצֶל כָּל יִשְׂרָאֵל כָּל אֶחָד וְאֶחָד לְפִי כֹּחוֹ, הַזְּקֵנִים לְפִי כֹּחָן, הַבַּחוּרִים לְפִי כֹּחָן, וְהַקְּטַנִּים לְפִי כֹּחָן, וְהַיּוֹנְקִים לְפִי כֹּחָן, וְהַנָּשִׁים לְפִי כֹּחָן, וְאַף משֶׁה לְפִי כֹּחוֹ, שֶׁנֶּאֱמַר (שמות יט, יט): משֶׁה יְדַבֵּר וְהָאֱלֹהִים יַעֲנֶנּוּ בְקוֹל, בְּקוֹל שֶׁהָיָה יָכוֹל לְסוֹבְלוֹ. וְכֵן הוּא אוֹמֵר (תהלים כט, ד): קוֹל ה' בַּכֹּחַ, בְּכֹחוֹ לֹא נֶאֱמַר אֶלָּא בַּכֹּחַ, בְּכֹחוֹ שֶׁל כָּל אֶחָד וְאֶחָד, וְאַף נָשִׁים מְעֻבָּרוֹת לְפִי כֹּחָן, הֱוֵי אוֹמֵר כָּל אֶחָד וְאֶחָד לְפִי כֹּחוֹ.
אָמַר רַבִּי יוֹסֵי בַּר חֲנִינָא אִם תָּמֵהַּ אַתָּה עַל הַדָּבָר הַזֶּה לְמֹד מִן הַמָּן שֶׁלֹא הָיָה יוֹרֵד לְיִשְׂרָאֵל אֶלָּא לְפִי כֹּחַ שֶׁל כָּל אֶחָד וְאֶחָד מִיִּשְׂרָאֵל, הַבַּחוּרִים הָיוּ אוֹכְלִין אוֹתוֹ כְּלֶחֶם, שֶׁנֶּאֱמַר (שמות טז, ד): הִנְנִי מַמְטִיר לָכֶם לֶחֶם מִן הַשָּׁמָיִם וגו'. וְהַזְּקֵנִים, כְּצַפִּיחִת בִּדְבָשׁ, שֶׁנֶּאֱמַר (שמות טז, לא): וְטַעֲמוֹ כְּצַפִּיחִת בִּדְבָשׁ. וְיוֹנְקִים, כְּחָלָב מִשְּׁדֵי אִמּוֹ, שֶׁנֶּאֱמַר (במדבר יא, ח): וְהָיָה טַעֲמוֹ כְּטַעַם וגו'. וְהַחוֹלִים כְּסֹלֶת מְעֹרָב בִּדְבַשׁ, שֶׁנֶּאֱמַר (יחזקאל טז, יט): וְלַחְמִי אֲשֶׁר נָתַתִּי לְךָ סֹלֶת וְשֶׁמֶן וּדְבַשׁ הֶאֱכַלְתִּיךָ. וְהָעוֹבְדֵי כּוֹכָבִים טָעֲמוּ אוֹתוֹ מַר וְגַד, שֶׁנֶּאֱמַר (במדבר יא, ז): וְהַמָּן כִּזְרַע גַּד הוּא. אָמַר רַבִּי יוֹסֵי בַּר רַבִּי חֲנִינָא וּמָה הַמָּן שֶׁהָיָה מִין אֶחָד נֶהְפַּךְ לְכַמָּה מִינִין בִּשְׁבִיל צֹרֶךְ כָּל אֶחָד וְאֶחָד, הַקּוֹל שֶׁהָיָה כֹּחַ בּוֹ עַל אַחַת כַּמָּה וְכַמָּה שֶׁהָיָה מִשְׁתַּנֶּה לְכָל אֶחָד וְאֶחָד שֶׁלֹא יִנָּזֵקוּ. וּמִנַּיִן שֶׁהַקּוֹל נֶחְלַק לְקוֹלוֹת הַרְבֵּה שֶׁלֹא יִנָּזֵקוּ, שֶׁנֶּאֱמַר (שמות כ, טו): וְכָל הָעָם רֹאִים אֶת הַקּוֹלֹת.
Come and see how the voice would go out among all of Israel - each and every one according to his strength: the elders according to their strength; the young men according to their strength; the infants according to their strength; the babies according to their strength; the women according to their strength; and even Moshe according to his strength, as it is stated (Exodus 19:19), "Moshe would speak and God would answer him with a voice" - with a voice that He could withstand. And so [too,] it states (Psalms 29:4), "The voice of the Lord is in strength" - it is not stated, "in His strength," but rather "in strength"; in the strength of each and every one, and even the pregnant women, according to their strength. Hence one would say each and every one according to his strength.
Rabbi Yose bar Chanina said, "If you wonder about this thing, learn from the manna, as it would only come down according to the strength of each and every one of Israel: the young men would eat it like bread, as it is stated (Exodus 16:4), 'Behold I will rain upon you bread from the skies, etc.'; the elders like a wafer in honey, as it is stated (Exodus 16:31), 'and its taste was like a wafer in honey'; the sucklings like the milk of it's mother's breast, as it is stated (Numbers 11:8), 'and its taste, was like the taste of, etc.'; the sick ones like fine flour mixed with honey, as it is stated (Ezekiel 16:19), 'And My bread that I gave you, fine flour and oil I fed you'; and the idolaters tasted it bitter and coriander, as it is stated (Numbers 11:7), 'And the manna was like coriander seed.'" And Rabbi Yose bar Rabbi Chanina said, "And since the manna which was one type switched to many types because of the need of each and every one, all the more so, the voice that had strength in it would change for each and every one, so that that they would not be injured, as it is stated (Exodus 20:15), 'And all the people saw the voices.'"
David Hartman, A Living Covenant, p.8
Belief in the giving of the Torah at Sinai does not necessarily imply that the full truth has already been given and that our task is only to unfold what was already present in the fullness of the founding moment of revelation. Sinai gave the community a direction, an arrow pointing toward a future filled with many surprises. Halakhah, which literally means “walking,” is like a road that has not been fully paved and completed. The Sinai moment of revelation, as mediated by the ongoing discussion in the tradition, invites one and all to acquire the competence to explore the terrain and extend the road. It does not require passive obedience and submission to the wisdom of the past.
Franz Rosenzweig in Revelation and Law, published in On Jewish Learning.
“Revelation is certainly not Law-giving. It is only this: Revelation. The primary content of revelation is revelation itself. ‘He came down’ (on Sinai) – this already concludes the revelation; “He spoke” is the beginning of the interpretation…”