Why did Moshe add the (otherwise superfluous) phrase "ve'Eis asher Yivchar bo Yakriv eilav"?
Ramban: He was adding that the one whom Hashem will choose will be the Kohen Gadol not only now, but for all future generations. 1
Seforno: He was warning them that he (the one whom He chooses) alone will emerge from the carnage that is about to take place. 2
On what pretext did Moshe postpone the test until the following day? What was his real motive?
Rashi: He told them that now was a time of drunkenness - when some of them had probably drunk wine, and it was not therefore possible to bring the Ketores. In fact, he did so in the hope that, in the meantime, they would come to their senses and retract.
Why does the Torah need to specifically mention "el Korach ve'el Kol Adaso"?
Seforno: Moshe was informing them that he saw through their plot and realized that the rebellion was pre-determined and not spontaneous. Refer to 16:2:2:1**.
What are the implications of the word "Boker Veyoda Hashem ? "?
Rashi: Moshe was hinting here that, just as it impossible to change morning into evening, so too, is it impossible to nullify the Kehunah from its current format. 1
Rashi: Seeing as, with reference to both issues, the Torah uses an expression of 'Havdalah' - "va'Yibadel Aharon Lehakdisho... "(Divrei ha'Yamim 1:23:13) and "va'Yehi Erev va'Yehi Voker va'Yavdel" (Bereishis, 1:5).
To whom does "Es asher Lo" and "ve'es ha'Kadosh" refer?
Rashi (citing Targum Onkelos): They refer, respectively, to those who are eligible for Avodas ha'Leviyah and Kehunah. 1
Seforno: Moshe was telling them that Hashem would make known the one who is speaking in honor of Hashem and the one who is holy and worthy of bringing Korbanos before Hashem, respectively.
Which the B'choros and Korach, respectively, were agitating for. See Ramban.
Why are tthe connotations of the (otherwise superfluous) phrase ?ve?eis asher Yivchar bo Yakriv eilav??
Seforno: It means that Hashem will separate the one whom He chooses ? and that he will save those who He does not choose with his merit.
Moshav Zekenim: Korach protested about three selections ? 1. Levi from Yisrael; 2. Aharon from the Levi'im; 3. Moshe to be the Navi and king. Consequently, he was now telling them that "Hashem will inform "Es asher Lo" ? the tribe of Levi 1 ; "ve'Es ha'Kadosh ve'Hikriv Eilav" ? Aharon 2 ; "ve'Eis asher Yivchar bo".
As the Torah wrote in 8:14 - "ve'Hayu Li ha'Levi'im".
As the Pasuk writes in Tehilim 106:16" - le'Aharon K'dosh Hashem".
Why does the Torah repeat the word "Eilav"?
Moshav Zekenim: Korach protested about three selections ? Levi from Yisrael, Aharon from the Levi'im, and Moshe to be the Navi and king. Consequently, he was now telling them that "Hashem will inform "Es asher Lo" ? Sheivet Levi ("ve'Hayu Li ha'Levi'im" ? 8:14); "ve'Es ha'Kadosh ve'Hikriv Eilav" ? Aharon ("le'Aharon K'dosh Hashem" ? Tehilim 106:16); "ve'Eis asher Yivchar bo" ? Moshe ("Lulei Moshe Bechiro" ? Tehilim 106:23).