They set out from Kadesh, and the Israelites, the whole congregation, came to Mount Hor.
Then the Lord said to Moses and Aaron at Mount Hor, on the border of the land of Edom,
"Let Aaron be gathered to his people. For he shall not enter the land that I have given to the Israelites, because you rebelled against my command at the waters of Meribah.
Take Aaron and his son Eleazar, and bring them up Mount Hor;
strip Aaron of his vestments, and put them on his son Eleazar. But Aaron shall be gathered to his people, and shall die there."
References for Numbers 20:26
Moses did as the Lord had commanded; they went up Mount Hor in the sight of the whole congregation.
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.
When all the congregation saw that Aaron had died, all the house of Israel mourned for Aaron thirty days.