Albert Barnes Commentary 2 Samuel 8:16-18

"And Joab the son of Zeruiah was over the host; and Jehoshaphat the son of Ahilud was recorder; and Zadok the son of Ahitub, and Ahimelech the son of Abiathar, were priests; and Seraiah was scribe; and Benaiah the son of Jehoiada [was over] the Cherethites and the Pelethites; and David`s sons were chief ministers." — 2 Samuel 8:16-18 (ASV)

For a similar account of the officers of Solomon’s kingdom, see 1 Kings 4:1–6, where Jehoshaphat is still the recorder, and Benaiah is promoted to be captain of the host in place of Joab. The recorder seems to have been a high officer of state, a kind of chancellor, whose duty was to keep a record of the kingdom’s events for the king’s information; as a result, he would naturally be the king’s adviser (Isaiah 36:22; 2 Chronicles 34:8). A similar office is found among the ancient Egyptians and Persians.

Ahimelech the son of Abiathar. According to 1 Samuel 22:9–23, Abiathar, Zadok’s colleague, was the son of Ahimelech. Abiathar the son of Ahimelech continued to be priest throughout the reign of David (compare to 1 Kings 1:7, 1 Kings 1:42, and 1 Kings 2:22–27). It almost necessarily follows that there is some error in the text.

The scribe. This refers to the secretary of state (2 Kings 12:10; 2 Kings 18:37), who was different from the military scribe (see the note on Judges 5:14).

The Cherethites and the Pelethites; Chief rulers (2 Samuel 8:18). The word כהן kôhên, translated here as “chief ruler,” is the standard word for a priest. In the early days of the monarchy, the word כהן kôhên had not yet entirely lost its original etymological sense, derived from a root meaning “to minister” or “to manage affairs,” even though in later times only its technical, priestly sense survived.