3:26 Then Joab left David and sent messengers after Abner. They brought him back from the well of Sirah. (But David was not aware of it.) 3:27 When Abner returned to Hebron, Joab took him aside at the gate as if to speak privately with him. Joab then stabbed him ¹  in the abdomen and killed him, avenging the shed blood of his brother Asahel. ² 

3:28 When David later heard about this, he said, “I and my kingdom are forever innocent before the Lord of the shed blood of Abner son of Ner! 3:29 May his blood whirl over ³  the head of Joab and the entire house of his father! ⁴  May the males of Joab’s house ⁵  never cease to have ⁶  someone with a running sore or a skin disease or one who works at the spindle ⁷  or one who falls by the sword or one who lacks food!”

3:30 So Joab and his brother Abishai killed Abner, because he had killed their brother Asahel in Gibeon during the battle.