5 And the king commanded Joab and Abishai and Ittai, saying, Deal gently for my sake with the young man, even with Absalom. And all the people heard when the king gave all the captains charge concerning Absalom. 6 So the people went out into the field against Israel: and the battle was in the forest of Ephraim. 7 And the people of Israel were smitten there before the servants of David, and there was a great slaughter there that day of twenty thousand men. 8 For the battle was there spread over the face of all the country; and the forest devoured more people that day than the sword devoured.
9 And Absalom chanced to meet the servants of David. And Absalom was riding upon his mule, and the mule went under the thick boughs of a great oak, and his head caught hold of the oak, and he was taken up between heaven and earth; and the mule that was under him went on. 10 And a certain man saw it, and told Joab, and said, Behold, I saw Absalom hanging in an oak. 11 And Joab said unto the man that told him, And, behold, thou sawest it, and why didst thou not smite him there to the ground? and I would have given thee ten [pieces of] silver, and a girdle. 12 And the man said unto Joab, Though I should receive a thousand [pieces of] silver in my hand, yet would I not put forth my hand against the king's son; for in our hearing the king charged thee and Abishai and Ittai, saying, Beware that none touch the young man Absalom. 13 Otherwise if I had dealt falsely against his life (and there is no matter hid from the king), then thou thyself wouldest have set thyself against [me]. 14 Then said Joab, I may not tarry thus with thee. And he took three darts in his hand, and thrust them through the heart of Absalom, while he was yet alive in the midst of the oak. 15 And ten young men that bare Joab's armor compassed about and smote Absalom, and slew him.
Matthew Henry's Commentary on 2 Samuel 18:5-15
Commentary on 2 Samuel 18:1-8
(Read 2 Samuel 18:1-8)
How does David render good for evil! Absalom would have only David smitten; David would have only Absalom spared. This seems to be a resemblance of man's wickedness towards God, and God's mercy to man, of which it is hard to say which is most amazing. Now the Israelites see what it is to take counsel against the Lord and his anointed.
Commentary on 2 Samuel 18:9-18
(Read 2 Samuel 18:9-18)
Let young people look upon Absalom, hanging on a tree, accursed, forsaken of heaven and earth; there let them read the Lord's abhorrence of rebellion against parents. Nothing can preserve men from misery and contempt, but heavenly wisdom and the grace of God.