Verse 1-6 — The length of this war tried the faith and patience of David, and made his settlement at last the more welcome. The contest between grace and corruption in the hearts of believers, may fitly be compared to this warfare. There is a long war between them, the flesh lusting against the spirit, and the spirit against the flesh; but as the work of holiness is carried on, corruption, like the house of Saul, grows weaker and weaker; while grace, like the house of David, grows stronger and stronger.
Verse 7-21 — Many, like Abner, are not above committing base crimes, who are too proud to bear reproof, or even the suspicion of being guilty. While men go on in sin, and apparently without concern, they are often conscious that they are fighting against God. Many mean to serve their own purposes; and will betray those who trust them, when they can get any advantage. Yet the Lord serves his own designs, even by those who are thus actuated by revenge, ambition, or lust; but as they intend not to honour him, in the end they will be thrown aside with contempt. There was real generosity both to Michal and to the memory of Saul, in David's receiving the former, remembering probably how once he owed his life to her affection, and knowing that she was separated from him partly by her father's authority. Let no man set his heart on that which he is not entitled to. If any disagreement has separated husband and wife, as they expect the blessing of God, let them be reconciled, and live together in love.
Verse 22-39 — Judgments are prepared for such scorners as Abner; but Joab, in what he did, acted wickedly. David laid Abner's murder deeply to heart, and in many ways expressed his detestation of it. The guilt of blood brings a curse upon families: if men do not avenge it, God will. It is a sad thing to die like a fool, as they do that any way shorten their own days, and those who make no provision for another world. Who would be fond of power, when a man may have the name of it, and must be accountable for it, yet is hampered in the use of it? David ought to have done his duty, and then trusted God with the issue. Carnal policy spared Joab. The Son of David may long delay, but never fails to punish impenitent sinners. He who now reigns upon the throne of David, has a kingdom of a nobler kind. Whatever He doeth, is noticed by all his willing people, and is pleasing to them.