LEV 10:6

6 Then Moses said to Aaron and to Eleazar and to Ithamar, his sons, “Do not let your hair on your heads hang loosely, and do not tear your clothes, so that you may not die, and so that Yahweh may not be angry with all the assembly. But allow your relatives, the entire house of Israel, to mourn for those whom the fire of Yahweh has set ablaze.