Numbers 3:4 YLT

²  And these 'are' the names of the sons of Aaron: the first-born Nadab, and Abihu, Eleazar, and Ithamar;

³  these 'are' the names of the sons of Aaron, the anointed priests, whose hand he hath consecrated for acting as priest.

⁴  And Nadab dieth -- Abihu also -- before Jehovah, in their bringing near strange fire before Jehovah, in the wilderness of Sinai, and sons they had not; and Eleazar -- Ithamar also -- acteth as priest in the presence of Aaron their father.

⁵  And Jehovah speaketh unto Moses, saying,

⁶  'Bring near the tribe of Levi, and thou hast caused it to stand before Aaron the priest, and they have served him,