2 Samuel 14:1

Now Joab the son of Zeruiah perceived that the king’s heart was toward Absalom.

Joab the son of Zeruiah perceived that the king's heart was toward Absalom, recognizing David's continuing deep affection for his son. Acting on that perception, he worked to bring father and son toward reconciliation. To that end he arranged for a wise woman from Tekoah to come and appeal to the king.

He twice succeeded in securing Absalom's reconciliation with David. Absalom betrayed that trust and became the instigator of rebellion against David. Despite David's love for his son, Joab killed Absalom when he found him helpless at the end of the battle.