Numbers 3:4

4 But Nadab and Abihu made an offering to the LORD by using fire that wasn't allowed. So they fell dead in front of him. That happened in the Desert of Sinai. They didn't have any sons. Only Eleazar and Ithamar served as priests while their father Aaron was living.

Numbers 3:4 In-Context

2 Aaron's oldest son was Nadab. His other sons were Abihu, Eleazar and Ithamar.
3 Those were the names of Aaron's sons. They were the anointed priests. They were prepared to serve the LORD as priests.
4 But Nadab and Abihu made an offering to the LORD by using fire that wasn't allowed. So they fell dead in front of him. That happened in the Desert of Sinai. They didn't have any sons. Only Eleazar and Ithamar served as priests while their father Aaron was living.
5 The LORD spoke to Moses. He said,
6 "Bring the men of the tribe of Levi to the priest Aaron. They will help him.
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