Absalom’s army defeated. (1-8):
David divided his troop into three and handed them over to Joab, his brother Abishai and Ittai, the Gittite. When David offered to go for the war, Joab opposed the idea in order to save David’s life. Because men of both David and Absalom believed that the success or failure depended on David’s life or death (Ahithopel in 17:3).
V. 5: Deal gently…with the young man Absalom…. There could be a fatherly love, or he would have thought his past life contributed toward Absalom’s ill-character.
Vs. 6-8: The forest of Ephraim: This is place is located on the east side of Jordon, which is not in Ephraim, in the vicinity of Mahanaim in Gilead. This place is known for its severe terrain, a thick forest. Through their past experience, David’s men are familiar with this forest. Due to their lack of familiarity, Absalom’s men had severe casualty than the casualty by war (V. 8).
V. 9 His head caought…“In God’s providence, the source of his pride became the cause of his downfall.” –ESV Study Bible. Refer 2 Sam 14:26.
He is slain. (9-18):
V. 12 …I would not raise my hand against the king’s son…King’s order in v. 5 is repeated here by a man who was questioned by Joab for not killing Absalom.
V. 14…took three spears in his hand and thrust them through Absalom’s heart. Even though Joab did a great favor to Absalom in Chapter 14 by talking with the king to bring reconciliation between Absalom and David, this time he does not want to spare as he feared Absalom to cause more problem again.
V. 16 Held back the people…Since Absalom is dead, Joab wants to spare people.
V. 18 I have no son…This is a reference to what Absalom did in the past. His reference about his sons in 14:27 contrasts the statement here. It is assumed that since 2 Samuel 14:27 doesn’t mention their names when it mentions the name of Tamar, that his sons died young.
King’s Valley Vs Kidron Valley:
The contrast is made between Absalom’s memorial pillar in Kings Valley and his tomb in Kidron Valley in Jerusalem.
David’s over-sorrow. (19-33):
Vs. 19-21: …You shall not take the news this day…. Joab did not want to send Ahimaaz probably because Joab Did not know how David would respond if he learnt the death of his son. In such scenario, he probably choose an unnamed Cushite, from Ethiopia over Ahimaaz. But it was not Joab’s intension to hide the news from David. Also, it is possible from verses 28 & 29, that Ahimaaz did not have clear information about Absalom and he had the knowledge that the war stopped for good and positive reason.
Verse 33… O! Absalom, my son, my son:
Some think David’s wish arose from concern about Absalom’s everlasting state; but he rather seems to have spoken without due thought. He is to be blamed for showing so great fondness for a graceless son. Also, for quarrelling with Divine justice. And for opposing the justice of the nation, which, as king, he had to administer, and which ought to be preferred before natural affection. The best men are not always in a good frame; we are apt to over-grieve for what we over-loved. But while we learn from this example to watch and pray against sinful indulgence, or neglect of our children, may we not, in David, perceive a shadow of the Saviour’s love, who wept over, prayed for, and even suffered death for mankind, though vile rebels and enemies. – Mathew Henry Commentary.
David is overcome with grief. He has lost another son whom he loved. First he lost Absalom’s love and loyalty, and now he has lost Absalom’s life and all hope of reconciliation. It is possible that David is beginning to see how God’s punishment for his sin with Bathsheba (prophesied by Nathan in12:10–11) has tragically come to pass; but his grief is clouding his sight of his duties toward his loyal troops (19:1–8). – ESV Study Bible.