וַיִּקַּ֣ח קֹ֔רַח בֶּן־יִצְהָ֥ר בֶּן־קְהָ֖ת בֶּן־לֵוִ֑י וְדָתָ֨ן וַאֲבִירָ֜ם בְּנֵ֧י אֱלִיאָ֛ב וְא֥וֹן בֶּן־פֶּ֖לֶת בְּנֵ֥י רְאוּבֵֽן׃ וַיָּקֻ֙מוּ֙ לִפְנֵ֣י מֹשֶׁ֔ה וַאֲנָשִׁ֥ים מִבְּנֵֽי־יִשְׂרָאֵ֖ל חֲמִשִּׁ֣ים וּמָאתָ֑יִם נְשִׂיאֵ֥י עֵדָ֛ה קְרִאֵ֥י מוֹעֵ֖ד אַנְשֵׁי־שֵֽׁם׃ וַיִּֽקָּהֲל֞וּ עַל־מֹשֶׁ֣ה וְעַֽל־אַהֲרֹ֗ן וַיֹּאמְר֣וּ אֲלֵהֶם֮ רַב־לָכֶם֒ כִּ֤י כָל־הָֽעֵדָה֙ כֻּלָּ֣ם קְדֹשִׁ֔ים וּבְתוֹכָ֖ם יְהוָ֑ה וּמַדּ֥וּעַ תִּֽתְנַשְּׂא֖וּ עַל־קְהַ֥ל יְהוָֽה׃ וַיִּשְׁמַ֣ע מֹשֶׁ֔ה וַיִּפֹּ֖ל עַל־פָּנָֽיו׃
Now Korah, son of Izhar son of Kohath son of Levi, betook himself, along with Dathan and Abiram sons of Eliab, and On son of Peleth—descendants of Reuben— to rise up against Moses, together with two hundred and fifty Israelites, chieftains of the community, chosen in the assembly, men of repute. They combined against Moses and Aaron and said to them, “You have gone too far! For all the community are holy, all of them, and the LORD is in their midst. Why then do you raise yourselves above the LORD’s congregation?” When Moses heard this, he fell on his face.
-- Rabbi Kenneth J. Weiss, 2004 in Voices of Torah, page 412-413.
Why does Korach rebel?
...Korach and company said that in view of the fact that the entire community was holy having experienced direct communication from God something not granted to any other nation, plus the fact that God remained within its midst, Moses and Aaron had placed themselves above such a holy nation. By saying "and God is in their midst," they [Korach and the rebellers] hinted that the presence of God was due to the people and not to the merit of Moses and Aaron.
Why did Moses then have the reaction of "falling on his face" (16:4)?
-- Rabbi Douglas E. Krantz, https://reformjudaism.org/learning/torah-study/korach/finding-ourselves-through-others
What do we learn from this?
