1. These are the groups to which the descendants of Aaron belong. Aaron had four sons: Nadab, Abihu, Eleazar, and Ithamar.
2. Nadab and Abihu died before their father did, and left no descendants, so their brothers Eleazar and Ithamar became priests.
3. King David organized the descendants of Aaron into groups according to their duties. He was assisted in this by Zadok, a descendant of Eleazar, and by Ahimelech, a descendant of Ithamar.