But Amasa did not notice the sword that was in Joab's hand. And he struck him with it in the stomach, and his entrails poured out on the ground; and he did not strike him again. Thus he died. Then Joab and Abishai his brother pursued Sheba the son of Bichri.
2 Samuel 20:10
Surrounding context
20:9 Then Joab said to Amasa, "Are you in health, my brother?" And Joab took Amasa by the beard with his right hand to kiss him.
20:10 But Amasa did not notice the sword that was in Joab's hand. And he struck him with it in the stomach, and his entrails poured out on the ground; and he did not strike him again. Thus he died. Then Joab and Abishai his brother pursued Sheba the son of Bichri.
20:11 Meanwhile one of Joab's men stood near Amasa, and said, "Whoever favors Joab and whoever is for David--follow Joab!"