Leviticus 10:6-7

6Then Moses said to Aaron, and to Eleazar and Ithamar his sons: “Do not uncover your heads or tear your clothes, so you may not die and He will not be angry with the entire congregation. But let your kinsmen—the whole house of Israel—mourn over the burning that Adonai has kindled.

7You must not go out from the entrance of the Tent of Meeting, or you will die, for the anointing oil of Adonai is on you.” So they acted according to the word of Moses.