Now Korah took (Numbers 16:1)
In the Midrash it is written: What did Korah see that caused him to begin a dispute with Moses? He saw the chapter of the red heifer.
This Midrash begs to be interpreted, and it appears to our master that Korah argued that since the whole congregation is holy and close to the Eternal, the people did not need the priests and the Levites to walk ahead of them to be ministers and judges and officers over them. It was, indeed, also the opinion of Moses, when he brought them out to the Mountain of G-d, to Horeb, that they should all be equals, a kingdom of priests and a holy nation, with no priest or leader to rule over them. However, the people refused to study themselves and did not want to hear the law and wisdom from the mouth of the Eternal, which was why they placed "נַעֲשֶׂה" (we will do) before "נִשְׁמָע" (we will study), because (Proverbs 24:7) "wisdom is too high for a fool" (רָאמוֹת לֶאֱוִיל חָכְמוֹת). So they made themselves a molten calf, saying "these are your gods, O Israel." For their souls desired abominations and a leader that would go before them and they after him, like an ox after his owner." (And see above פרשת תרומה and פרשת כי תשא where our master has elaborated on this.)
Now it is known that when the Israelites approached Mount Sinai their filth was terminated (פסקה זוהמתן) and they became immortal. However, when they turned to idols and they made an idol of gold, their filth was restored as before and their mortality was decreed for the generations. And it was concerning this that Asaph took up his song (Psalms 82:6) "I said: you are like godlike beings" (אֲנִי אָמַרְתִּי אֱלֹהִים אַתֶּם), for you all would become like the gods that you wanted to go before you. And you would have been the leaders. "Nevertheless" (אָכֵן), when you chose iniquity and idols, the filth was restored, and therefore "you shall die like men" (כְּאָדָם תְּמוּתוּן).
In this light, we can understand the connection between the red heifer and the sin of the calf which occasioned the Midrash (Numbers Rabbah 19:8) "let the mother come and clear away the filth" (tavo imo v'tiqanah et ha-tzo'ah). For after the sin of the calf, G-d said (Exodus 32:34) "and in the day when I visit, I will visit their sin upon them" (וּבְיוֹם פָּקְדִי וּפָקַדְתִּי עֲלֵהֶם חַטָּאתָם). And our master has already explained that the day of visiting (יום פקודה) is the day of death, as it is written (Numbers 16:29) "and if they be visited after the visitation of all men (וּפְקֻדַּת כָּל הָאָדָם יִפָּקֵד עֲלֵיהֶם). So when each of the Children of Israel will die and his earthly sojourn will be remembered, he will cause the sin of the calf, which brought death back to the world, to be remembered as well. This is the meaning of "and in the day when I visit, I will visit their sin upon them." And that is why the red heifer, which purifies the ritual impurity of death, atones for the sin of the calf, which is remembered on the day that a man dies. והבן כי הדברים עתיקים.
In the future, when the world will be perfected in the kingdom of the Almighty and He will execute the angel of death, the sin of the calf will be completely forgiven and will never be recalled or remembered again. In this light we may understand why the Sages of Secrets possessed of the Divine Secret wrote that in the future Korah will be vindicated in judgment and his righteousness will be clearly apparent. And they hinted at this because the final letters of the words "צדיק כתמר יפרח" (the righteous shall flourish like a palm tree) spell קרח (i.e. Korah). According to what was said, we can understand this very well, because Korah and Moses our teacher both held the same opinion before Israel committed the sin of the calf. If so, when the world will be filled with knowledge and the Eternal alone will be exalted, all Israel will be at the top of the stairs (בגרם המעלות), no princes will raise themselves above them nor kings reign over them.
And these are the words of the Midrash. For Korah risked his life to differ with Moses, because he saw the chapter of the red heifer and from the multitude of ideas within him he believed that the heifer would cleanse completely the sin of the calf and transform entirely the spirit of impurity. He therefore stood up to argue with Moses and Aaron and said (Numbers 16:4) "for all the congregation are holy, every one of them, and why do you lift yourselves above the assembly of the Eternal?"
וַיִּלֹּנוּ כָּל עֲדַת בְּנֵי יִשְׂרָאֵל מִמָּחֳרָת, עַל מֹשֶׁה וְעַל אַהֲרֹן לֵאמֹר אַתֶּם הֲמִתֶּם אֶת עַם יְהוָה
But on the next day all the congregation of the people of Israel murmured against Moses and against Aaron, saying, You have killed the people of the Lord. (Numbers 17:6)
See the Ramban who explained that the people complained that Moses induced the assembly of Korah to offer strange incense as a result of which they died, even though the Eternal never commanded Moses to do so. They blamed Moses for not choosing a different sign by which to prove that Aaron was the holy one.
Now one may ask why, indeed, did Moses act in this way towards those men. Why did he not choose a different sign? Is not the only reason for their death that they offered a strange incense? For it is written explicitly (Numbers 16:35): "And there came out a fire from the Lord, and consumed the two hundred and fifty men that offered incense (וְאֵשׁ יָצְאָה מֵאֵת יְהוָה וַתֹּאכַל אֵת הַחֲמִשִּׁים וּמָאתַיִם אִישׁ מַקְרִיבֵי הַקְּטֹרֶת)."
And it appears to our master that the Malbim has explained that each of these quarrelsome men who were convened against the Eternal and His anointed one was seeking his own glory. And every one of them was driven by a spirit of dominion, each wishing to become priest or prophet. Korah thought that, as the son of Izhar, he was worthy of becoming king, while Dathan and Abiram felt that, as descendants of Reuven, the eldest son of Jacob, they were entitled to the birthright. And the two hundred and fifty men were princes of the congregation called into the assembly, men of renown, who were preeminent among the people. But none of them revealed his true desire to the other lest the package come unraveled, and everyone return to his own home. For why should one get angry in a quarrel that was not his? Each one, therefore, placed a mask over his true face by saying "all the congregation are holy," so that each one could be a priest in his own house, and each would help his friend and encourage his brother to take down Aaron from his position. But each one, in his heart, imagined himself, after Aaron was stripped of his position, as priest in Aaron's stead and as master over his brothers.
However, the mightiest of the prophets understood the thoughts of these plotters of iniquity and wanted to undermine their plan, so he commanded them to offer incense. And although they planned a deception and spoke deceitfully, Moses thought that they would finally retreat in shame and each one would admit that he was seeking only his own glory rather than allow his allies to approach the altar to perform a service that would consume any layman who performed it. Why would anyone condemn his friend and colleague to death to be consumed by fire? Moses therefore expected that, as a result, all the workers of iniquity would be scattered (יתפרדו כל פועלי און). Instead, however, they stiffened their necks and defiantly approached to offer the incense.