ויפשט משה את אהרן את בגדיו וילבש אתם אלעזר בנו וימת אהרן
Ramban explains that the garments which Aharon HaKohen wore were the begadim, vestments, of the Kohen Gadol. Elazar, his son, was now being inducted into Kehunah Gedolah, High Priesthood, by wearing these vestments. Apparently, he had just concluded his Priestly service by: offering the Korban Tamid shel bein ha’arbaim, afternoon continued offering; burning the Incense; and kindling the menorah. Moshe brought Aharon up to Har Hohor, while he was still wearing the vestments. He then stripped him of them and dressed Elazar. According to the simple p’shat, plain understanding, Moshe dressed Aharon in tachrichim, burial shrouds. He then removed Elazar’s…
