Numbers 3:4

4 Nadab and Abihu died before the Lord when they offered unholy fire before the Lord in the wilderness of Sinai, and they had no children. Eleazar and Ithamar served as priests in the lifetime of their father Aaron.

Numbers 3:4 In-Context

2 These are the names of the sons of Aaron: Nadab the firstborn, and Abihu, Eleazar, and Ithamar;
3 these are the names of the sons of Aaron, the anointed priests, whom he ordained to minister as priests.
4 Nadab and Abihu died before the Lord when they offered unholy fire before the Lord in the wilderness of Sinai, and they had no children. Eleazar and Ithamar served as priests in the lifetime of their father Aaron.
5 Then the Lord spoke to Moses, saying:
6 Bring the tribe of Levi near, and set them before Aaron the priest, so that they may assist him.
New Revised Standard Version Bible, copyright 1989, Division of Christian Education of the National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved.