Numbers 3:4-6

New King James Version

^4 (A)Nadab and Abihu had died before the Lord when they offered profane fire before the Lord in the Wilderness of Sinai; and they had no children. So Eleazar and Ithamar ministered as priests in the presence of Aaron their father.

The Levites Serve in the Tabernacle

⁵ And the Lord spoke to Moses, saying: ^6 (B)“Bring the tribe of Levi near, and present them before Aaron the priest, that they may serve him.