Leviticus 10:6 TLB

[6] Then Moses said to Aaron and his sons Eleazar and Ithamar, "Do not mourn-do not let your hair hang loose as a sign of your mourning, and do not tear your clothes. If you do, God will strike you dead too, and his wrath will come upon all the people of Israel. But the rest of the people of Israel may lament the death of Nadab and Abihu, and mourn because of the terrible fire the Lord has sent.