Charles Ellicott Commentary 2 Samuel 8:17

"and Zadok the son of Ahitub, and Ahimelech the son of Abiathar, were priests; and Seraiah was scribe;" — 2 Samuel 8:17 (ASV)

Ahimelech, the son of Abiathar. —So Ahimelech is also described in 1 Chronicles 18:16; 1 Chronicles 24:6; on the other hand, Abiathar is expressly said to be the son of Ahimelech in the narrative in 1 Samuel 22:20–23. This difficulty is increased by the further mentions of the men bearing these names.

Ahimelech was certainly the high priest who gave the shew-bread to David, and was slain as a result by Saul (1 Samuel 21-22), and Abiathar, who fled to David, and afterwards became high priest, and was finally removed from the high-priesthood by Solomon (1 Kings 1:2), was certainly his son; but on the other hand, in 1 Chronicles 24:3; 1 Chronicles 24:6; 1 Chronicles 24:31, Ahimelech is said to have been the co-priest with Zadok during the reign of David, and our Lord says that David ate the shew-bread in the days of Abiathar, the high priest (Mark 2:26).

These apparently conflicting facts have caused unnecessary perplexity. The simple solution to the difficulty seems to be that both names were borne alike by father and by son, so that both of them are spoken of sometimes under one name, sometimes under the other.

On the double high-priesthood of Zadok and Abiathar, see Note at the beginning of 2 Samuel 6.