But David answered Rechab and Baanah his brother, the sons of Rimmon the Beerothite, “As the LORD lives, who has redeemed my life out of every adversity,
We have here justice done upon the murderers of Ish-bosheth. I. Sentence passed upon them. There needed no evidence, their own tongues witnessed against them; they were so far from denying the fact that they gloried in it. David therefore shows them the heinousness of the crime, and that blood called for blood from his hand, who was now the chief magistrate, and was by office the avenger of blood.
Commenting on 2 Samuel 4:9-12
When one told me, saying, behold, Saul is dead,.... No more is related, not that he killed him, or assisted in killing him, only that he was dead; by which it appears, as Abarbinel thinks, that the Amalekite did not slay Saul, and that David did not put him to death on that account, but for what follows: thinking to have brought good tidings; which...
Who hath redeemed my soul out of all adversity - This was, in David's case, a very proper view of the goodness and watchful providence of God towards him. His life was frequently in danger; murderers had often laid wait for it: but God, the living God, had always redeemed that life from all adversity; and called on him now to punish such evil-minded and blood-thirsty men.