Numbers 20:23-29

23There, on the border of the land of Edom, the Lord said to Moses and Aaron,

24“The time has come for Aaron to join his ancestors in death. He will not enter the land I am giving the people of Israel, because the two of you rebelled against my instructions concerning the water at Meribah.

25Now take Aaron and his son Eleazar up Mount Hor.

26There you will remove Aaron’s priestly garments and put them on Eleazar, his son. Aaron will die there and join his ancestors.”

27So Moses did as the Lord commanded. The three of them went up Mount Hor together as the whole community watched.

28At the summit, Moses removed the priestly garments from Aaron and put them on Eleazar, Aaron’s son. Then Aaron died there on top of the mountain, and Moses and Eleazar went back down.

29When the people realized that Aaron had died, all Israel mourned for him thirty days.