Then Moses said to Aaron and his sons Eleazar and Ithamar, “Do not show grief by leaving your hair uncombed or by tearing your clothes. If you do, you will die, and the Lord’s anger will strike the whole community of Israel. However, the rest of the Israelites, your relatives, may mourn because of the Lord’s fiery destruction of Nadab and Abihu.
4
Aaron and his two surviving sons are forbidden to show the accustomed signs of mourning, or to leave the court of the tabernacle to attend the fune…

Uncover not your heads. —Better, let not your heads be dishevelled. It was the custom for mourners to let their hair grow…

And Moses said to Aaron, and to Eleazar, and to Ithamar,
his sons
His two younger son…

The most quieting considerations during affliction are drawn from the word of God. What was it that God spoke? Though Aaron's heart must have been …
Albert Barnes
AlbertBarnes