In previous chapters we have seen the rebellion of son against father, but today we see the reckoning of the Lord. God will use all the previous happenings to purge David's kingdom and separate the loyal from the disloyal. We see that when God's judgments fall, they fall swiftly and accurately.
Chapter 17 records the death of Ahithophel. There is no question that Ahithophel's plan was the better of the two, but God saw to it that Absalom rejected it. Note Hushai's psychological approach in suggesting that Absalom lead the army himself (chapter 17:11). This appealed to Absalom's vanity, but vanity only led to his death. When Ahithophel saw that his counsel was rejected, he took his own life.
Chapter 18 records the death of Absalom. The vain prince followed Hushai's advice and led his army into the wood of Ephraim. He was certainly not prepared to wage war, and again we see that "pride goeth before destruction, and an haughty spirit before a fall" (Proverbs 16:18). Absalom caught his head and long hair in a branch and could not get down. Joab disobeyed David's command and killed the rebel; then he sent the news to the king. David wept bitterly when he heard the news that his son Absalom was dead.
Although Absalom had conspired viciously against King David, David still loved him. Absalom was still his son. David had never become bitter at him. In fact, his abnormal grief at Absalom's death almost cost him the kingdom!
We need to continually pray that we will never become bitter in our old age. There is nothing more pitiful than an old, bitter Christian. If the Lord tarries, and we are allowed to live, we will all become old. If we live in the Word and walk in the Spirit, we can grow sweeter as the years go by. David was, indeed, "a man after God's own heart." I believe this attribute of "sweetness" was one of his greatest marks of distinction.
