Numbers 20:22-29
Aaron dies
22 All the Israelites travelled from Kadesh to Mount Hor. 23 When they were there, at the border of Edom's land, the Lord spoke to Moses and Aaron. 24 He said, ‘Aaron will soon die. He will not go into the land that I am giving to the Israelites. That is because you both refused to obey me at Meribah. 25 Moses, you must take Aaron and his son Eleazar to climb up Mount Hor. 26 Take the priest's clothes from Aaron and put them on Eleazar. Aaron will die there.’
27 Moses did what the Lord told him to do. Moses, Aaron and Eleazar climbed up Mount Hor, while the Israelites watched. 28 Moses took the priest's clothes from Aaron and he put them on Eleazar. Aaron died there, at the top of the mountain. Moses and Eleazar walked back down the mountain. 29 The Israelites realized that Aaron had died. They wept for 30 days because of his death.