61 Yet Nadab and Abihu died when they offered alien fire before the LORD.
Numbers 26:61 Cross References - VIN
Leviticus 10:1-2
Numbers 3:4
4 Nadab and Abihu died in the LORD's presence because they offered unauthorized fire in his presence in the Desert of Sinai. They had no children. So only Eleazar and Ithamar served as priests during the lifetime of their father Aaron.