Numbers 20:22-29

22So the entire company of Israelites traveled from Kadesh and came to Mount Hor.

23And the Lord spoke to Moses and Aaron in Mount Hor, by the border of the land of Edom. He said:

24“Aaron will be gathered to his ancestors, for he will not enter into the land I have given to the Israelites because both of you rebelled against my word at the waters of Meribah.

25Take Aaron and Eleazar his son, and bring them up on Mount Hor.

26Remove Aaron’s priestly garments and put them on Eleazar his son, and Aaron will be gathered to his ancestors and will die there.”

27So Moses did as the Lord commanded; and they went up Mount Hor in the sight of the whole community.

28And Moses removed Aaron’s garments and put them on his son Eleazar. So Aaron died there on the top of the mountain. And Moses and Eleazar came down from the mountain.

29When all the community saw that Aaron was dead, the whole house of Israel mourned for Aaron thirty days.