Numbers 20:22-29

Now the children of Israel, the whole congregation, journeyed from Kadesh and came to Mount Hor. And the LORD spoke to Moses and Aaron in Mount Hor by the border of the land of Edom, saying: “Aaron shall be gathered to his people, for he shall not enter the land which I have given to the children of Israel, because you rebelled against My word at the water of Meribah. Take Aaron and Eleazar his son, and bring them up to Mount Hor; and strip Aaron of his garments and put them on Eleazar his son; for Aaron shall be gathered to his people and die there.” So Moses did just as the LORD commanded, and they went up to Mount Hor in the sight of all the congregation. Moses stripped Aaron of his garments and put them on Eleazar his son; and Aaron died there on the top of the mountain. Then Moses and Eleazar came down from the mountain. Now when all the congregation saw that Aaron was dead, all the house of Israel mourned for Aaron thirty days.