They that hate me without a cause are more than the hairs of mine head (comp. Psalms 35:14; and for the simile. comp. Psalms 40:12; both of them Davidical compositions). They that would destroy me, being mine enemies wrongfully, are mighty.
Joab and Abiathar, who supported the rebellion of Adonijah (1 Kings 1:7), and were "mighty" men, certainly were David's enemies "wrongfully." And the same may be said of Absalom and Ahithophel. Then I restored that which I took not away.
Dr. Kay supposes David's quasi-abdication of a crown which he had not placed on his own head (2 Samuel 15:14-17) to be alluded to.