Bible Verses About Aaron: Forbidden to mourn the death of his sons, Nadab and Abihu

Then Moshe told Aharon and his sons El'azar and Itamar, "Don't unbind your hair or tear your clothes in mourning, so that you won't die and so that ADONAI won't be angry with the entire community. Rather, let your kinsmen - the whole house of Isra'el -mourn, because of the destruction ADONAI brought about with his fire.

Aharon answered Moshe, "Even though they offered their sin offering and burnt offering today, things like these have happened to me! If I had eaten the sin offering today, would it have pleased ADONAI?"