II Samuel 3:20-25

So Abner and twenty men with him came to David at Hebron. And David made a feast for Abner and the men who were with him. Then Abner said to David, “I will arise and go, and 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. At that moment the servants of David and Joab came from a raid and brought much spoil with them. But Abner was not with David in Hebron, for he had sent him away, and he had gone in peace. When Joab and all the troops that were with him had come, they told Joab, saying, “Abner the son of Ner came to the king, and he sent him away, and he has gone in peace.” Then Joab came to the king and said, “What have you done? Look, Abner came to you; why is it that you sent him away, and he has already gone? Surely you realize that Abner the son of Ner came to deceive you, to know your going out and your coming in, and to know all that you are doing.”