Numbers 20:27

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.

At this chapter begins the history of the fortieth year (which was the last year) of the Israelites' wandering in the wilderness. And since the beginning of their second year, when they were sentenced to perform their quarantine in the desert, there to wear away the tedious revolution of forty years, there is little recorded concerning them till this last year, which brought them to the borders of Canaan, and the history of this year is almost as large as the history of the first year. This chapter gives an account of, I. The death of Miriam (Num 20:1). II. The fetching of water out of the rock, in which observe, 1. The distress Israel was in, for want of water (Num 20:2). 2. Their discontent and murmuring in that distress (Num 20:3-5). 3. God's pity and power engaged for their supply with water out of the rock (Num 20:6-9). 4. The infirmity of Moses and Aaron upon this occasion (Num 20:10, Num 20:11). 5. God's displeasure against them (Num 20:12, Num 20:13). III. The negotiation with the Edomites. Israel's request (Num 20:14-17), and the repulse the Edomites gave them (Num 20:18-21). IV. The death of Aaron the high priest upon Mount Hor, the instalment of Eleazar in his room, and the people's mourning for him (Num 20:22, etc.).

20:27-29 Priestly authority was transferred when Moses placed Aaron’s priestly garments (cp. Lev 8:7-9) on Eleazar. Afterward, Aaron died at the age of 123, in the fortieth year after the Hebrews left Egypt (see Num 33:37-39). • all Israel mourned for him thirty days: This was an unusually high honor (see also Deut 34:8), since the normal period of public mourning was seven days (Gen 50:10; 1 Sam 31:13).