Numbers 3:2-4 NIV

2 The names of the sons of Aaron were Nadab the firstborn1 and Abihu, Eleazar and Ithamar.2

References for Numbers 3:2

3 Those were the names of Aaron's sons, the anointed priests,3 who were ordained to serve as priests.

References for Numbers 3:3

4 Nadab and Abihu, however, fell dead before the LORD 4 when they made an offering with unauthorized fire before him in the Desert of Sinai.5 They had no sons; so only Eleazar and Ithamar6 served as priests during the lifetime of their father Aaron.7

References for Numbers 3:4