2nd Samuel 3:28

25 Is it not clear to you that Abner, the son of Ner, came with deceit to get knowledge of your going out and your coming in and of all you are doing?

26 And when Joab had come out from David, he sent men after Abner, and they overtook him at the water-spring of Sirah, and made him come back with them: but David had no knowledge of it.

27 And when Abner was back in Hebron, Joab took him on one side by the doorway of the town to have a word with him quietly, and there he gave him a wound in the stomach, causing his death in payment for the death of his brother Asahel.

28 And when David had word of it he said, May I and my kingdom be clear for ever in the eyes of the Lord from the blood of Abner, the son of Ner:

29 May it come on the head of Joab and all his father's family: among the men of Joab's family may there ever be some who are diseased or lepers, or who do the work of women, or are put to the sword, or are wasted from need of food!

30 So Joab and Abishai his brother put Abner to death, because he had put to death their brother Asahel in the fight at Gibeon.

31 And David said to Joab and all the people who were with him, Go in grief and put haircloth about you, in sorrow for Abner. And King David went after the dead body.