?Ve'hafshet es Aharon es Begadav?. Whar procedure did Moshe follow?
Rashi #1: It is referring to the Bigdei Kehunah Gedolah which Moshe first dressed Aharon, 1 then removed and dressed Elazar. 2
Rashi #2 (in Ha'azinu Devarim, 32:50) and Ramban (citing the Sifra): He (miraculously) removed each of the Bigdei Kehunah Gedolah from Aharon 3 - in the order that Aharon put them on - and dressed Elazar with it in front of Aharon, before removing the next Beged and dressing Elazar.
Ramban: Aharon ascended the mountain still dressed in his Bigdei Kehunah after bringing the Korban Tamid and the Ketores. Then Moshe removed them and placed them on Elazar after dressing Aharon with the shrouds that he had prepared for him.
Seforno: Moshe removed the four garments of the Kohen Gadol from Aharon 4 and placed them on Elazar - who was already dressed in the four garments of a Kohen Hedyot. 5
See Sifsei Chachamim.
Thereby inaugurating him as Kohen Gadol. See also Ba'al ha'Turim.
Ramban: After Hashem had dressed him with Bigdei Shechinah underneath. See Ramban.
Seforno: Leaving him dressed in the four garments that he wore when he entered the Kodesh Kodshim on Yom Kipur - in the way that the Mal'achei Elokim appear to Hashem's servants.
This is unlike opinion of Rebbi (in Yoma 23b), who says that the Avnet of a Kohen Hedyot is different than that of a Kohen Gadol. (PF)
Why did Moshe have to remove Aharon's Begadim and dress Elazar? Why could Aharon and Elazar not do it themselves?
Oznayim la'Torah: Ever since Hashem sanctified Shabbos - at the Creation, when Yisrael were not yet there to sanctify it, Hashem appointed the leaders of Yisrael in their varios capacities to sanctify whatever requires sanctification. 1 Consequently, Moshe was required to consecrate Elazar into the Kehunah Gedolah by dressing him in the Bigdei Kehunah Gedolah (And he needed to remove the Begadim from Aharon, due to the miracle that accompanied the removal). 2
Why could Aharon simply not remove the Bigdei Kehunah Gedolah whilst still in the camp and Moshe could dress Elazar when they returned from Hor ha'Har?
Rashi (in Ha?azinu): In order that Aharon should see Elazar dressed in the Begadim before he died.
Oznayim la?Torah: So that people should see Elazar in the Bigdei Kehunah Gedolah before they had a chance to challenge his right to succeed Aharon - since the episode with Korach was still on their mind.
Because Aharon was destined to wear the Bigdei Kehunah Gedolah until moments before he died, when Hashem dressed him in Bigdei Shechinah. 1
Refer to 20:26:1:2*.
What is the significance of the fact that Moshe dressed Elazar in the Begadim of Aharon?
Rashi (in Shmuel 1, 2:30): It meant that Hakadosh-Baruch-Hu had appointed him in place of Aharon as Kohen Gadol.
Why did Moshe not anoint Elazar with the Shemen ha'Mishchah?
Oznayim la'Torah: Bedause he had already been anointed with the Shemen ha'Mishchah when he became a Kohen Hedyot. Consequently now, wearing the Bigdei Kehunah Gedolah sufficed to consecrate him
How could Aharon wear his garments there, seeing as one may not wear the Bigdei Kehunah outside of the Azarah!
Hadar Zekenim #1 (on 19:18): The Isur to take them outside is only at the time of Avodah. This is somewhat like 'Kehunah applies to Aharon's descendants only when they wear the Bigdei Kehunah.'
Hadar Zekenim #2 (on 19:18): It was a Hora'as Sha'ah (a momentary ruling) [to permit wearing them outside].
