6 While there was war between the house of Saul and the house of David, Abner was making himself strong in the house of Saul.
7 Now Saul had a concubine whose name was Rizpah daughter of Aiah. And Ishbaal said to Abner, "Why have you gone in to my father's concubine?" 8 The words of Ishbaal made Abner very angry; he said, "Am I a dog's head for Judah? Today I keep showing loyalty to the house of your father Saul, to his brothers, and to his friends, and have not given you into the hand of David; and yet you charge me now with a crime concerning this woman. 9 So may God do to Abner and so may he add to it! For just what the Lord has sworn to David, that will I accomplish for him, 10 to transfer the kingdom from the house of Saul, and set up the throne of David over Israel and over Judah, from Dan to Beer-sheba." 11 And Ishbaal could not answer Abner another word, because he feared him. 12 Abner sent messengers to David at Hebron, saying, "To whom does the land belong? Make your covenant with me, and I will give you my support to bring all Israel over to you."
Matthew Henry's Commentary on 2 Samuel 3:6-12
Commentary on 2 Samuel 3:1-6
(Read 2 Samuel 3:1-6)
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.
Commentary on 2 Samuel 3:7-21
(Read 2 Samuel 3:7-21)
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.