So Moses did as the LORD had commanded, and they climbed Mount Hor in the sight of the whole congregation.
The chapter began with the funeral of Miriam, and it ends with the funeral of her brother Aaron. When death comes into a family, it often strikes double. Israel had not improved the former affliction they were under, by the death of the prophetess, and therefore, soon after, God took away their priest, to try if they would lay that to heart.
Commenting on Numbers 20:22-29
And Moses stripped Aaron of his garments,.... His priestly garments, which, very probably, were put on at the foot of the mountain, on purpose for the transaction of this affair, since they were not in common worn, but only when in service; the same hands that clothed Aaron with them at first, stripped him of them, and both were done at the command of God...
Num 20:27-29 Moses executed this command, and Aaron died upon the top of the mountain, according to Num 33:37-38, on the first day of the fifth month, in the fortieth year after the Exodus from Egypt, at the age of 123 years (which agrees with Exo 7:7), and was mourned by all Israel for thirty days.
Commenting on Numbers 20:27-29