2 Samuel 18:1-17
18:1-4 David sent his troops into battle against his son Absalom. David’s men insisted that he remain behind in Mahanaim (2 Sam. 17:24,27) since all of Absalom’s men would be seeking to kill him.

18:5 The king commanded [likely out of love for his son and in spite of his son’s treachery and destructive ambition] Joab [oldest son of David’s sister Zeruiah (2 Sam. 2:13; 1 Chron. 2:16); overall military commander during most of David’s reign; name means “Yahweh is father”], Abishai [Joab’s brother; name means “father exists”] and Ittai [a Philistine loyal to David; name means “with God”], “Be gentle [indicates that David did not desire vengeance; cf. Rom. 12:19-21] with the young man Absalom [name means “father of peace”] for my sake.” And all the troops heard [thus no one could claim ignorance] the king giving orders concerning Absalom to each of the commanders.

18:6-8 David’s troops defeated Absalom’s troops in a battle in the forest of Ephraim.

18:9-13 Absalom’s hair became entangled in a tree as he rode through the forest, thus leaving him in a vulnerable position. One of David’s men reported this incident to Joab.

18:14 Joab [Joab had killed in cold blood before (2 Sam. 3:27)] said [perhaps motivated by the belief that, if left alive, Absalom might seize an opportunity to kill David and take the throne], “I’m not going to wait like this for you [Joab believed he needed to seize the opportunity himself; took matters into his own hand].” So he [Joab consciously disobeyed David’s clear and direct order] took three javelins [refers to some kind of shafted weapon; can also mean “rod,” “dart,” or “spear”] in his hand and plunged them into Absalom’s heart while Absalom was still alive in the oak tree.

18:15-17 Ten of Joab’s men joined in the brutal murder of Absalom and then unceremoniously buried him in a pit in the forest.

2 Samuel 18:32-33
18:32 The king asked [direct question; king still concerned about welfare of his wayward son] the Cushite, “Is the young man Absalom safe [or, “Is there peace (shalom) for the young man Absalom?”]?” The Cushite replied [indirect answer], “May the enemies of my lord the king and all who rise up to harm you be like that young man.”

18:33 The king was shaken [cf. 1 Sam. 14:15 and Joel 2:10 re: shaking of the ground; same word translated “tremble” in Deut. 2:25 and Joel 2:1]. He went up to the room over the gateway and wept. As he went [these words suggest that David was overcome with grief and wept before he made it all the way to the room over the gateway], he said: “O my son Absalom! My son, my son Absalom! If only I had died instead of you—O Absalom, my son, my son!”