1 Chronicles 24:1 YLT

¹  And to the sons of Aaron 'are' their courses: sons of Aaron 'are' Nadab, and Abihu, Eleazar, and Ithamar,

²  and Nadab dieth, and Abihu, in the presence of their father, and they had no sons, and Eleazar and Ithamar act as priests.

³  And David distributeth them, and Zadok of the sons of Eleazar, and Ahimelech of the sons of Ithamar, according to their office in their service;