出エジプト記 19:9

בעב הענן signifies in the thickness of the cloud, and this is the ערפל, the thick darkness mentioned in Exodus 20:18 “And Moses stepped near unto the thick darkness where God was” (Mekhilta). וגם בך AND IN THEE ALSO [WILL THEY BELIEVE] — The word “also” implies that they will believe also in the prophets who will come after thee (Mekhilta). ויגד משה את דברי וגו׳ AND MOSES TOLD THE WORDS OF [THE PEOPLE UNTO THE LORD] on the following day which was the fourth of the month. את דברי העם וגו׳ THE WORDS OF THE PEOPLE etc. — He said to God: “I have heard from them a reply to this statement — that their desire is to hear the commandments from You and not from me. One who hears from the mouth of a messenger is not the same (in the same position) as one who hears directly from the mouth of the King himself. It is our wish to see our King (cf. Mekhilta).

וַיֹּ֨אמֶר יְהֹוָ֜ה אֶל־מֹשֶׁ֗ה הִנֵּ֨ה אָנֹכִ֜י בָּ֣א אֵלֶ֘יךָ֮ בְּעַ֣ב הֶֽעָנָן֒ בַּעֲב֞וּר יִשְׁמַ֤ע הָעָם֙ בְּדַבְּרִ֣י עִמָּ֔ךְ וְגַם־בְּךָ֖ יַאֲמִ֣ינוּ לְעוֹלָ֑ם וַיַּגֵּ֥ד מֹשֶׁ֛ה אֶת־דִּבְרֵ֥י הָעָ֖ם אֶל־יְהֹוָֽה׃

And the Lord said to Moshe, Lo, I come to thee in a thick cloud, that the people may hear when I speak with thee, and believe thee for ever. And Moshe told the words of the people to the Lord.