8 When they arrived at Hebron, they presented Ishbosheth's head to David. "Look!" they exclaimed to the king. "Here is the head of Ishbosheth, the son of your enemy Saul who tried to kill you. Today the Lord has given my lord the king revenge on Saul and his entire family!"
9 But David said to Recab and Baanah, "The Lord, who saves me from all my enemies, is my witness. 10 Someone once told me, 'Saul is dead,' thinking he was bringing me good news. But I seized him and killed him at Ziklag. That's the reward I gave him for his news! 11 How much more should I reward evil men who have killed an innocent man in his own house and on his own bed? Shouldn't I hold you responsible for his blood and rid the earth of you?" 12 So David ordered his young men to kill them, and they did. They cut off their hands and feet and hung their bodies beside the pool in Hebron. Then they took Ishbosheth's head and buried it in Abner's tomb in Hebron.
Matthew Henry's Commentary on 2 Samuel 4:8-12
Commentary on 2 Samuel 4:8-12
(Read 2 Samuel 4:8-12)
A person may be glad to obtain his just wishes, and yet really regret the means by which he receives them. He may be sorry for the death of a person by which he is a gainer. These men shed innocent blood, from the basest motives. David justly executed vengeance upon them. He would not be beholden to any to help him by unlawful practices. God had helped him over many a difficulty, and through many a danger, therefore he depended upon him to crown and complete his own work. He speaks of his redemption from all adversity, as a thing done; though he had many storms yet before him, he knew that He who had delivered, would deliver.