And Abner conferred with the elders of Israel, saying, “For some time past you have been seeking David as king over you. Now then bring it about, for the Lord has promised David, saying, ‘By the hand of my servant David I will save my people Israel from the hand of the Philistines, and from the hand of all their enemies.’” Abner also spoke to Benjamin. And then Abner went to tell David at Hebron all that Israel and the whole house of Benjamin thought good to do.
When Abner came with twenty men to David at Hebron, David made a feast for Abner and the men who were with him. And Abner said to David, “I will arise and go and will gather all Israel to my lord the king, that they may make a covenant with you, and that you may reign over all that your heart desires.” So David sent Abner away, and he went in peace.
Just then the servants of David arrived with Joab from a raid, bringing much spoil with them. But Abner was not with David at Hebron, for he had sent him away, and he had gone in peace. When Joab and all the army that was with him came, it was told Joab, “Abner the son of Ner came to the king, and he has let him go, and he has gone in peace.” Then Joab went to the king and said, “What have you done? Behold, Abner came to you. Why is it that you have sent him away, so that he is gone? You know that Abner the son of Ner came to deceive you and to know your going out and your coming in, and to know all that you are doing.” 2 Samuel 3:17-25.
Abner had gone to some trouble to install Ish-bosheth as king, but now he seems to have regrets. He sees that the Lord is with David, and he decides to get the whole kingdom together under David.
Joab, David’s lieutenant, does not buy it. He accuses Abner of being a spy, and decides to kill him. David does not know that Joab is going to murder Abner.
Joab is another one of these people who acts on his own, doing what is right in his own eyes. He thinks he knows better than David, and he presumes to know what’s going on here.
Few if us will be tempted to act on actual assassination plots, but we all tend to run our mouths without adequate knowledge or good judgement. Character assassination is as common as pollen.