Bamidbar 20:28-29

Orthodox Jewish Bible

²⁸ And Moshe stripped Aharon of his garments, and put them upon Eleazar bno; and Aharon died there on the top of the mount; and Moshe and Eleazar came down from the mount.

²⁹ And when Kol HaEdah saw that Aharon was dead, they mourned for Aharon shloshim yom, even Kol Bais Yisroel.