Numbers 20:27-29

Amplified Bible

²⁷ So Moses did just as the Lord had commanded; and they went up Mount Hor in the sight of all the congregation. ²⁸ After Moses stripped Aaron of his [priestly] garments and put them on Eleazar his son, Aaron died there on the mountain top. Then Moses and Eleazar came down from the mountain. ²⁹ When all the congregation saw that Aaron had died, all the house of Israel wept (mourned) for him thirty days.