Numbers 16:1 to 18:32, First Samuel 11:14 to 12:22
In verse 11:29 Moshe shared his desire that all the Israelites would have God's Spirit and prophecy. When speaking with Korach, Moshe is upset because Korach is "against Adonai" (verse 16:11), not because Moshe is selfishly power-hungry. Moshe is not opposed to others receiving power or authority from God, but he recognizes that demanding what God has not given is rebellion.
Notice that Numbers 8:19 specifically links the obedience of priests and Levites with the prevention of plague.
Note that in verse 16:22 the verb ye'cheta is in the future tense. Rashi offers a precise translation (below) but does not explain why the verb is in the future tense. Perhaps Moshe and Aharon are worried that if they, as the proper leaders, in the future sin then the entire community could be punished.
Verse 16:1 says Korach "took" but does not specify what he took. One rabbinical conjecture relates this verse to the ones previous; my paraphrase follows:
Aharon and Moshe were the children of Amram, firstborn of Kehas son of Levi.
Korach's wife, eager to show him pious as the firstborn of Kehas's second son, sewed him a garment entirely from the blue threads specified for the tzitzit in verse 15:38. Korach wore it before Moshe, and asked, "Is this not better than a single thread of blue?" Moshe disagreed, and said that according to God's recent decree even an all-blue garment needs fringes with a blue thread. Korach than begain stirring up trouble by saying, "Just as my garment is all blue threads and should not need one extra blue thread, so the people are holy and should not need Aharon and his sons."
Many people of the tribe of Reuven joined Korach, for they were bitter that Reuven's birthright (doubled portion) as firstborn of Israel had been given to Ephraim (Yosef's second son) and saw Moshe's selection of Yehoshua of Ephraim as a deliberate insult.
On son of Peles is not mentioned after verse 16:1. Just as Korach was provoked to rebel by his wife, On was saved by his rightous wife who convinced him that night to leave the rebellion.
Ramban writes that all 250 members of Korach's rebellion were firstborn, wanting to serve as priests. Rashi and R'Bechaye add that Korach's sons did not agree with their father's ambition, and thus were spared (Numbers 26:11) and became the ancestors of Shmuel and other prophets.
Rashi notes that the letter hey in the word ha'eesh (verse 16:22) has as its vowel a kametzh, and precedes a noun (eesh) starting with the letter alef. This shows that the hey does not start a question but is a simple direct article. The second half of the verse should be translated "The one man will sin. And upon all the community you will be angry?" Rashi's intention is to avoid any translation that suggests God would punish people for sins God knows the person will commit in the future.
Why did the people accuse Moshe and Aharon of killing Korach and his followers, when it was so clealy an act of God? One theory of Rashi's is that the people thought Moshe and Aharon had put poison in the incense pans. This is why Moshe had Aharon stop the plague with an incense pan: so they people would admit they were mistaken and repent.
The K'li Yakar notices that verse 16:34 says nasu le'kolam (they fled to the voice) instead of nasu mi'kolam (they fled from the voice). He suggests that as the descendents of Korach fell they shouted confessions, and the people approached to hear these and so avoid making the same mistakes.
The Maharal compares Korach's sin (wanting to ignite mutiny and split the camp) with his punishment (being burned and falling into a split in the ground).
Notice how Moshe prays for the people no matter how often they rebel against him personally. The Tz'enah Ur'enah comments that leadership is responsible for blessing the people both proactively and in response to circumstance.
If a person accidentally killed another, he must stay in one of the cities of sanctuary until the death of the High Priest. Because the High Priest did not pray that there be no accidental murder in his time, the accidental killer prays for the speedy death of the High Priest, so that he may leave the city.
Richard Hirsch uses the Korach rebellion to ponder issues of modern Jewish authority:
Put differently, to what degree is the authority to interpret and adjust Judaism to be reserved for rabbis trained in and conversant with the Jewish legal tradition (the "Halakha", or Jewish law), and to what degree is that authority to be shared with reasonably informed and involved Jewish laypeople?
Orthodoxy, asserting the divine origin and binding nature of Torah and Halakha, reserves the right for rabbis only.
Conservative Judaism affirms the binding nature of Halakha, while believing in the right of rabbis to make changes within the Halakhic system. The input of laypeople, however, is considered important in determining which changes the community is prepared to accept, or needs to have enacted on its behalf.
Reform Judaism, which in fact traces its origins to the modernizing actions first of laypeople and later on of rabbis in several congregations in Germany in the 19th century, has always allowed a voice from the community to inform its policies and platforms.
Reconstructionist Judaism has perhaps most enthusiastically embraced the idea of a lay-rabbinic partnership in formulating a modern interpretation of Judaism, with its recent liturgy, platforms, and policies being the result of such collaboration...
There is a sharp and important difference between a reform from within the system and an attack upon the system... Notwithstanding our differences, the story of Korach teaches us that for our discussions to be productive, we must strive for them to be "for the sake of Heaven".
Ismar Schorsch notes that in the Parasha's Haftorah, God may have given approval to annoint Shaul as King because Shmuel's sons were unworthy of becoming judges in the manner that Shmuel judged Israel.
The Imrei Shefer notes that the fire pans used to cover "the altar" must have gone onto the outside altar, for the inside (incence) altar was not visible to the community and thus coating it would not have served as a reminder.
There is a rabbinic legend (gemara Chulin 60b) that the moon and sun were originally the same size, but when the moon complained to God that it should be prominent over the sun then God instead punished the moon's pride by shrinking it. The Ohr Pnei Moshe of Pshavorsk writes that this legend was known to the ancient Israelites, and Moshe postponed the confrontation until morning so Korach's followers might see the moon that night, remember the story, and repent.
Dr. Avigdor Bonchek notes Moshe's modesty in verses 16:29-30. Moshe says that if the miracle does not happen it is a mark against him, and if the miracle does happen it is a mark against Korach's rebellion. Moshe could have emphasized (but did not) that if the miracle happened it was proof that God bestowed authority on Moshe.