2 Samuel 3:25 (KJV)

When Joab and all the host that was with him were come, they told Joab, saying, Abner the son of Ner came to the king, and he hath sent him away, and he is gone in peace.

Then Joab came to the king, and said, What hast thou done? behold, Abner came unto thee; why is it that thou hast sent him away, and he is quite gone?

Thou knowest Abner the son of Ner, that he came to deceive thee, and to know thy going out and thy coming in, and to know all that thou doest.

And when Joab was come out from David, he sent messengers after Abner, which brought him again from the well of Sirah: but David knew it not.

And when Abner was returned to Hebron, Joab took him aside in the gate to speak with him quietly, and smote him there under the fifth rib, that he died, for the blood of Asahel his brother.