In the Book of Bamidbar, which takes place at the same time as Vayikra, we read of a forgetful ungrateful people, who had just been rescued from slavery in Egypt by a very powerful Gd. Last week in Parshat Shlach, it seems unthinkable, but ten of the twelve tribal leaders, who enter the Promised Land on a pilot trip to stake out which section of Land would go for each  tribe, end up coming to the conclusion that there's no way they can conqueror the locals and live safely.

For that bad, rebellious and chutzpadik decision they're condemned to die within a short time, and the Jewish People must wander the wilderness for forty years. Only the next generation will enter the Land.

Next comes Korach. Korach is from the the tribe of Levy. Now, Levy is the tribe that Gd appointed to be in charge of the spiritual needs of the Jewish People. One branch of the tribe was appointed by Gd to be the Priests, and other branches were given specific jobs to do in the Mishkan, Tabernacle and later the Holy Temple.

Korach isn't a "happy camper." He's obviously jealous of cousins who are priests, especially Moses.

Numbers Chapter 16

1Korah the son of Izhar, the son of Kohath, the son of Levi took [himself to one side] along with Dathan and Abiram, the sons of Eliab, and On the son of Peleth, descendants of Reuben.		אוַיִּקַּ֣ח קֹ֔רַח בֶּן־יִצְהָ֥ר בֶּן־קְהָ֖ת בֶּן־לֵוִ֑י וְדָתָ֨ן וַֽאֲבִירָ֜ם בְּנֵ֧י אֱלִיאָ֛ב וְא֥וֹן בֶּן־פֶּ֖לֶת בְּנֵ֥י רְאוּבֵֽן:
2They confronted Moses together with two hundred and fifty men from the children of Israel, chieftains of the congregation, representatives of the assembly, men of repute.		בוַיָּקֻ֨מוּ֙ לִפְנֵ֣י משֶׁ֔ה וַֽאֲנָשִׁ֥ים מִבְּנֵֽי־יִשְׂרָאֵ֖ל חֲמִשִּׁ֣ים וּמָאתָ֑יִם נְשִׂיאֵ֥י עֵדָ֛ה קְרִאֵ֥י מוֹעֵ֖ד אַנְשֵׁי־שֵֽׁם:
3They assembled against Moses and Aaron, and said to them, "You take too much upon yourselves, for the entire congregation are all holy, and the Lord is in their midst. So why do you raise yourselves above the Lord's assembly?"		גוַיִּקָּֽהֲל֞וּ עַל־משֶׁ֣ה וְעַל־אַֽהֲרֹ֗ן וַיֹּֽאמְר֣וּ אֲלֵהֶם֘ רַב־לָכֶם֒ כִּ֤י כָל־הָֽעֵדָה֙ כֻּלָּ֣ם קְדשִׁ֔ים וּבְתוֹכָ֖ם יְהֹוָ֑ה וּמַדּ֥וּעַ תִּתְנַשְּׂא֖וּ עַל־קְהַ֥ל יְהֹוָֽה:

By blaming Moses and Aaron, Korach is distorting/denying the divinity of Judaism.

Bamidbar - Numbers - Chapter 3

10You shall appoint Aaron and his sons, and they shall keep their kehunah; any outsider [non kohen] who approaches shall be put to death.

יוְאֶת־אַֽהֲרֹ֤ן וְאֶת־בָּנָיו֙ תִּפְקֹ֔ד וְשָֽׁמְר֖וּ אֶת־כְּהֻנָּתָ֑ם וְהַזָּ֥ר הַקָּרֵ֖ב יוּמָֽת:

In Korach's rebellion he gathers others dissatisfied with their roles, but soon they are defeated.

We must remember that Judaism is from Gd, and we don't have the authority to make changes. It's not a club.