Which clothes is the Pasuk referring to?
Rashi (in Devarim 32:50) and Ramban #2 (citing the Toras Kohanim): He (miraculously) removed the Bigdei Kehunah Gedolah from Aharon 3 and placed them on Elazar, garment by garment, in the correct order, in front of Aharon.
Ramban #1: 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