Aaron and his two surviving sons are forbidden to show the accustomed signs of mourning, or to leave the court of the tabernacle in order to attend the funeral, because, from their office, they were especially concerned as consecrated priests in outwardly maintaining the honor of Yahweh. They were to bear visible testimony to the righteousness of the punishment of Nadab and Abihu. The people, on the other hand, as not formally standing so near to Yahweh, were permitted to “bewail” as an acknowledgment that the nation had a share in the sin of its priests. (Compare 1 Corinthians 12:26.)
Uncover not your heads - Or, “set free ... let go loose.” It was a custom to let the hair grow long and fall loosely over the head and face Leviticus 13:45; 2Sa 15:30; 2 Samuel 19:4; and the substance of the command would thus be that they should not let the hair go disheveled. Ripping the clothes in front so as to lay open the breast was one of the most common manifestations of grief (see Genesis 37:29; Gen 44:13; 2 Samuel 1:11; Job 1:20; Joel 2:13, etc.). The garments as well as the persons of the priests were consecrated; this appears to be the reason of the prohibition of these ordinary signs of mourning. Compare Leviticus 20:10.
Lest ye die - See Exodus 28:35 note.
The anointing oil ... is upon you - See Leviticus 8:12, Leviticus 8:30. The holy oil, as the symbol of the Holy Spirit, the Spirit of Life and immortality and joy, was the sign of the priests being brought near to Yahweh. It was therefore by its meaning connected both with the general law which forbade the high priest ever to put on signs of mourning on account of death Leviticus 21:10-12, and with the special reason for the prohibition on this occasion.