Judging that there could be no safety to the king, nor peace to the kingdom, nor security to himself, and all David's friends and loyal subjects, and good men, if Absalom had lived, as may seem probable from 2 Samuel 19:10, and yet perceiving that the king's heart was reconcilable to Absalom, notwithstanding his abominable crimes of lying with his father's concubines, and of horrid and unnatural rebellion; both which were capital crimes by the law of God; he adventured to save David's life against his will. But whether Joab did well in this, all things considered, I shall not here determine.
Related Commentaries of 2 Samuel 18:15
2 Samuel 18:15
15 And ten young men that bare Joab's armour compassed about and smote Absalom, and slew him.