Numbers 20:27-29

New Revised Standard Version, Anglicised

²⁷ Moses did as the Lord had commanded; they went up Mount Hor in the sight of the whole congregation. ²⁸ Moses stripped Aaron of his vestments, and put them on his son Eleazar; and Aaron died there on the top of the mountain. Moses and Eleazar came down from the mountain. ²⁹ When all the congregation saw that Aaron had died, all the house of Israel mourned for Aaron for thirty days.