Who is "Es Kol ha'Eidah" referring to?
Rashi: It refers to the entire congregation - whom he spent the night inciting against Moshe. 1
Ramban: It refers, either to the leaders of the congregation, who always assembled at the entrance of the Ohel Mo'ed, or the B'chorim, who were fit to perform the Avodah. 2
Refer to 16:19:2:1*.
Ramban: It cannot mean literally the entire congregation, since, in Pasuk 21, the Torah does not add "ve'E'eseh oscha le'Goy Gadol".
How did Korach gather all the congregation?
Rashi: The entire night he went from tribe to tribe, mocking Moshe, 1 explaining to the people that he was fighting, not only for himself, but on behalf of all of them 2 - to counter Moshe for taking the kingship for himself and the Kehunah for his brother, until he won them all over.
Targum Yonasan: To win over the people with his vast wealth - which he obtained when he discovered two storehouses 3 full of silver and gold, which Yosef had put away for Par'oh.
Ba?al ha?Turim: Because, thinking that he was about to be appointed Kohen Gadol, he did like was done for Aharon when he was appointed. 4
There is nothing that can compete with Letzanus to attract people and win them over. See Oznayim la'Torah DH ''va'Yakhel aleihem Korach' #1 & #2.
See Pasuk 3 and refer to 16:7:2:1**, 16:2:3:2*. See also Ba'al ha'Turim.
By distributing gifts to all the people. He obtained this wealth by finding two of the storehouses (See Peirush Yonasan) containing all the wealth of Egypt that Yosef had hidden. Da'as Zekenim (32:1): Pesachim 119a: There were two rich Chachamim in the world, Korach and Haman; both perished from the world on account of heir wealth - as the Pasuk writes in Koheles 5:12 "Osher Shamur li'Ve'alav le'Ra'aso" - Because it was not a gift from Hashem, but they grabbed it for themselves.
See Tzav Vayikra, 8:3.
What does the Torah mean when it writes that "Vayeira K'vod Hashem ... " ?
Rashi: It means that the Glory of Hashem appeared in the form of a Pillar of Cloud. 1
See Sifsei Chachamim.
What is the significance of the Pillar of Cloud appearing at that moment to all the people?
Targum Yonasan: It came in defense of Moshe and Aharon, whom Korach wanted to drive out of this world with his wealth.
Moshav Zekenim (citing R. Eliezer of Garmaiza): Hashem appeared in Person to punish them in case people say that Moshe killed them with the Name of Hashem. 1
Moshav Zekenim (Ibid.): To no avail, since they said to Moshe and Aharon accusingly (in 17:6) 'You killed the Am Hashem!'
