Numbers 3:4-6

Douay-Rheims 1899 American Edition

⁴ Now Nadab and Abiu died, without children, when they offered strange fire before the Lord, in the desert of Sinai: and Eleazar and Ithamar performed the priestly office in the presence of Aaron their father.

⁵ And the Lord spoke to Moses, saying:

⁶ Bring the tribe of Levi, and make them stand in the sight of Aaron the priest to minister to him, and let them watch,