"And all the people saw the voices" (Exodus 20:15). Rabbi Yehudah says: when a person speaks with his fellow he hears the sound of his voice but does not see its light; but Israel heard the voice of the Holy One, blessed be He, and saw the voice going forth from the mouth of the Almighty in lightning and thunder, as it is said "And all the people saw the voices." Rabbi Pinchas says: that entire generation who heard the voice of the Holy One, blessed be He, merited to be like the ministering angels. No kind of vermin had power over them, and at their death no worm had power over them. Happy are they in this world and in the world to come; concerning them Scripture says "Happy is the people for whom it is so" (Psalms 144:15).
Israel Saw the Voices at Sinai and Became Like Angels
Yalkut Shimoni on Torah 299:3
(שמות כ טו) וְכָל הָעָם רֹאִים אֶת הַקּוֹלֹת, רַבִּי יְהוּדָה אוֹמֵר אָדָם מְדַבֵּר עִם חֲבֵרוֹ הוּא שׁוֹמֵעַ רֶגֶשׁ קוֹלוֹ אֲבָל אֵינוֹ רוֹאֶה מְאוֹרוֹ, וְיִשְׂרָאֵל שָׁמְעוּ קוֹל שֶׁל הַקָּדוֹשׁ בָּרוּךְ הוּא וְרָאוּ אֶת הַקּוֹל יוֹצֵא מִפִּי הַגְּבוּרָה בִּבְרָקִים וּרְעָמִים, שֶׁנֶּאֱמַר וְכָל הָעָם רֹאִים אֶת הַקּוֹלֹת. רַבִּי פִּנְחָס אוֹמֵר כָּל אוֹתוֹ הַדּוֹר שֶׁשָּׁמְעוּ קוֹלוֹ שֶׁל הַקָּדוֹשׁ בָּרוּךְ הוּא זָכוּ לִהְיוֹת כְּמַלְאֲכֵי הַשָּׁרֵת, וְלֹא שָׁלַט בָּהֶן כָּל מִין כִּנִּים, וּבְמוֹתָם לֹא שָׁלְטָה בָּהֶם רִמָּה, אַשְׁרֵיהֶם בָּעוֹלָם הַזֶּה וְלָעוֹלָם הַבָּא, עֲלֵיהֶם הַכָּתוּב אוֹמֵר "אַשְׁרֵי הָעָם שֶׁכָּכָה לוֹ".