Another interpretation of "the chariots of God" (Psalms 68:18): Rabbi Eleazar ben Pedat said, in a place where there are crowds there is crush, but at Sinai, when the Holy One, blessed be He, came, there came down with Him a thousand thousands and myriads of myriads, and even so there was room for them, as it says "thousands of angels [shin'an]" (Psalms 68:18) [reading shin'an as a term of ease], as you say "Moab has been at ease [sha'anan] from its youth" (Jeremiah 48:11). Rabbi Eleazar ben Azariah and Rabbi Eleazar of Modiin: one of them says the mountain itself stretched to hold them, for the Holy One, blessed be He, said to it, Lengthen yourself, widen yourself, and receive the children of your Master. And one says, when the Holy One, blessed be He, returns to Jerusalem He will bring the exiles back into her, as it says "these shall come from far" (Isaiah 49:12). Can she hold them? Rather the Holy One, blessed be He, said to her, "Enlarge the place of your tent" (Isaiah 54:2). "The LORD is among them" (Psalms 68:18): Reish Lakish said, every single angel has a tablet upon his heart, and the Name of the Holy One, blessed be He, is joined to the name of the angel: Mi-cha-el, Gav-ri-el, Refa-el. "The LORD is among them" means His lordship is among them. And do not say among them alone, but even when He came to give His Torah, in this very tongue He gave it, and opened with it: "I am the LORD your God" (Exodus 20:2). This is what Scripture says: "Hear, My people, and I will speak" (Psalms 50:7). Rabbi Hama bar Isaac said, "Hear, My people, that I may speak," that I may have an opening of the mouth to bring charges against the princes of the nations of the world. Another interpretation: "Hear, My people" refers to the past. Before you accepted the Torah, your names were like the names of the nations of the world: "Seba, and Havilah, and Sabtah, and Raamah, and Sabteca" (Genesis 10:7). Once you accepted the Torah you became "My people": "God, your God, am I" (Psalms 50:7).
Thousands of Angels and Yet Room to Spare at Sinai
Yalkut Shimoni on Torah 286:4
דָּבָר אַחֵר "רֶכֶב אֱלֹהִים" אָמַר רַבִּי אֶלְעָזָר בֶּן פְּדָת, בְּמָקוֹם שֶׁיֵּשׁ אוּכְלוּסִין יֵשׁ דֹּחַק, אֲבָל בְּסִינַי כְּשֶׁבָּא הַקָּדוֹשׁ בָּרוּךְ הוּא יָרְדוּ עִמּוֹ אֶלֶף אֲלָפִים וְרִבֵּי רְבָבוֹת, אַף עַל פִּי כֵן הָיָה לָהֶם רֵיוַח, שֶׁנֶּאֱמַר "אַלְפֵי שִׁנְאָן" כְּמָה דְאַתְּ אָמֵר (ירמיה מח, יא) "שַׁאֲנָן מוֹאָב מִנְּעוּרָיו". רַבִּי אֶלְעָזָר בֶּן עֲזַרְיָה וְרַבִּי אֶלְעָזָר הַמּוֹדָעִי אֶחָד מֵהֶן אוֹמֵר וּמַחֲזִיק הָיָה הָהָר, אֶלָּא אָמַר לוֹ הַקָּדוֹשׁ בָּרוּךְ הוּא הַאֲרֵךְ הַרְחֵב וְקַבֵּל בְּנֵי אֲדוֹנֶיךָ, וְאֶחָד אוֹמֵר כְּשֶׁיָּשׁוּב הַקָּדוֹשׁ בָּרוּךְ הוּא לִירוּשָׁלַיִם הוּא מַחֲזִיר אֶת הַגָּלֻיּוֹת לְתוֹכָהּ, שֶׁנֶּאֱמַר "אֵלֶּה מֵרָחוֹק יָבֹאוּ" יְכוֹלָה הִיא לְהַחֲזִיק אֶלָּא אָמַר לָהּ הַקָּדוֹשׁ בָּרוּךְ הוּא (שם נד, ב) "הַרְחִיבִי מְקוֹם אָהֳלֵךָ". "ה' בָם" אָמַר רֵישׁ לָקִישׁ טַבְלָא יֵשׁ לוֹ עַל לִבּוֹ שֶׁל כָּל מַלְאַךְ וּמַלְאָךְ וּשְׁמוֹ שֶׁל הַקָּדוֹשׁ בָּרוּךְ הוּא מְשֻׁתָּף בִּשְׁמוֹ שֶׁל מַלְאָךְ, מִיכָאֵל גַּבְרִיאֵל רְפָאֵל. "ה' בָם" אַדְנוּתוֹ בָּהֶם וְאַל תֹּאמַר בָּהֶם בִּלְבַד, אֶלָּא אַף בְּשָׁעָה שֶׁבָּא לִיתֵּן תּוֹרָתוֹ בַּלָּשׁוֹן הַזֶּה נְתָנָהּ וּפָתַח בּוֹ אָנֹכִי ה' אֱלֹהֶיךָ. זֶה שֶׁאָמַר הַכָּתוּב (תהלים נ, ז) "שִׁמְעָה עַמִּי וַאֲדַבֵּרָה". אָמַר רַבִּי חָמָא בַּר יִצְחָק "שִׁמְעָה עַמִּי" שֶׁאֲדַבְּרָה שֶׁיְּהֵא לִי פִּתְחוֹן פֶּה לְקַטְרֵג לְשָׂרֵי אֻמּוֹת הָעוֹלָם, דָּבָר אַחֵר "שִׁמְעָה עַמִּי" לְשֶׁעָבַר עַד שֶׁלֹּא קִבַּלְתֶם הַתּוֹרָה שִׁמְכֶם יִשְׂרָאֵל כִּשְׁמוֹתָם שֶׁל אֻמּוֹת הָעוֹלָם, (בראשית י, ז) "סְבָא וַחֲוִילָה וְסַבְתָּה וְרַעְמָה וְסַבְתְּכָא", מִשֶּׁקִּבַּלְתֶּם אֶת הַתּוֹרָה עַמִּי, "אֱלֹהִים אֱלֹהֶיךָ אָנֹכִי".