2 Samuel 3:20-25

When Abner, who had twenty men with him, came to David at Hebron, David prepared a feast for him and his men. Then Abner said to David, “Let me go at once and assemble all Israel for my lord the king, so that they may make a covenant with you, and that you may rule over all that your heart desires.” So David sent Abner away, and he went in peace. Just then David’s men and Joab returned from a raid and brought with them a great deal of plunder. But Abner was no longer with David in Hebron, because David had sent him away, and he had gone in peace. When Joab and all the soldiers with him arrived, he was told that Abner son of Ner had come to the king and that the king had sent him away and that he had gone in peace. So Joab went to the king and said, “What have you done? Look, Abner came to you. Why did you let him go? Now he is gone! You know Abner son of Ner; he came to deceive you and observe your movements and find out everything you are doing.”