Numbers 3:4-6

Living Bible

⁴ But Nadab and Abihu died before the Lord in the wilderness of Sinai when they used unholy fire. And since they had no children, this left only Eleazar and Ithamar to assist their father, Aaron.

⁵ Then the Lord said to Moses, ⁶ “Summon the tribe of Levi and present them to Aaron as his assistants.