Aaron married Elisheba,
daughter of Amminadab and sister of Nahshon.
She bore him Nadab and Abihu, Eleazar and Ithamar.

“Have your brother Aaron, with his sons, come to you from the Israelites to serve Me as priest—Aaron, his sons Nadab and Abihu, Eleazar and Ithamar.

This is the inventory for the tabernacle, the tabernacle of the testimony, that was recorded at Moses’ command. It was the work of the Levites under the direction of Ithamar son of Aaron the priest.

Then Moses said to Aaron and his sons Eleazar and Ithamar, “Do not let your hair hang loose and do not tear your garments, or else you will die, and the Lord will become angry with the whole community. However, your brothers, the whole house of Israel, may mourn over that tragedy when the Lord sent the fire.

Moses spoke to Aaron and his remaining sons, Eleazar and Ithamar: “Take the grain offering that is left over from the fire offerings to the Lord, and eat it prepared without yeast beside the altar, because it is especially holy.

Later, Moses inquired about the male goat of the sin offering, but it had already been burned up. He was angry with Eleazar and Ithamar, Aaron’s surviving sons, and asked,

These are the names of Aaron’s sons: Nadab, the firstborn, and Abihu, Eleazar, and Ithamar.

But Nadab and Abihu died in the Lord’s presence when they presented unauthorized fire before the Lord in the Wilderness of Sinai, and they had no sons. So Eleazar and Ithamar served as priests under the direction of Aaron their father.

This is the service of the Gershonite clans at the tent of meeting, and their duties will be under the direction of Ithamar son of Aaron the priest.

This is the service of the Merarite clans regarding all their work at the tent of meeting, under the direction of Ithamar son of Aaron the priest.”

and gave the Merarites four carts and eight oxen corresponding to their service, under the direction of Ithamar son of Aaron the priest.

Nadab, Abihu, Eleazar, and Ithamar were born to Aaron,

Amram’s children: Aaron, Moses, and Miriam.
Aaron’s sons: Nadab, Abihu, Eleazar, and Ithamar.

The divisions of the descendants of Aaron were as follows: Aaron’s sons were Nadab, Abihu, Eleazar, and Ithamar.

But Nadab and Abihu died before their father, and they had no sons, so Eleazar and Ithamar served as priests.

Together with Zadok from the sons of Eleazar and Ahimelech from the sons of Ithamar, David divided them according to the assigned duties of their service.

Since more leaders were found among Eleazar’s descendants than Ithamar’s, they were divided accordingly: 16 heads of ancestral houses were from Eleazar’s descendants, and eight heads of ancestral houses were from Ithamar’s.

They were assigned by lot, for there were officers of the sanctuary and officers of God among both Eleazar’s and Ithamar’s descendants.

The secretary, Shemaiah son of Nethanel, a Levite, recorded them in the presence of the king and the officers, Zadok the priest, Ahimelech son of Abiathar, and the heads of families of the priests and the Levites. One ancestral house was taken for Eleazar, and then one for Ithamar.

Gershom, from Phinehas’s descendants;
Daniel, from Ithamar’s descendants;
Hattush, from David’s descendants,