2 Samuel 3:26-28 Modern English Version (MEV)
26 When Joab left David, he sent messengers after Abner, and they brought him back from the well of Sirah. However, David was not aware of this. 27 So Abner returned to Hebron, and Joab pulled him aside in the gateway so as to speak with him undisturbed. There he struck him in the midsection so that he died on account of the blood of Asahel, his brother.
28 Afterward when David heard of this, he said, “My kingdom and I are forever blameless before the Lord for the blood of Abner the son of Ner.