Zadok and Ahimelech (rather Abiathar, see 1 Chronicles 24:6) assisted David in drawing up the priestly courses, as the “captains of the host” assisted him in making the divisions of the singers 1 Chronicles 25:1.
Related Commentaries of 1 Chronicles 24:3
1 Chronicles 24:3
3 And David distributed them, both Zadok of the sons of Eleazar, and Ahimelech of the sons of Ithamar, according to their offices in their service.