2 Samuel 20:7-10

7So Joab’s men went after him, along with [David’s bodyguards] the Cherethites and Pelethites and all the warriors; they went out from Jerusalem to pursue Sheba the son of Bichri.

8When they were at the great stone in Gibeon, Amasa came to meet them. Now Joab was wearing his military uniform, and over it he had a belt with a sheathed sword strapped around his hips; and as he went forward, it fell out.

9Joab said to Amasa, “Is it going well with you, my brother?” And with his right hand Joab took hold of Amasa by the beard [as if] to kiss him [in greeting].

10But Amasa [who had replaced Joab as David’s commander] was off guard and not attentive to the sword in Joab’s hand. So Joab struck Amasa in the abdomen with the sword, spilling his intestines to the ground. Without another blow Amasa died. Then Joab and Abishai his brother pursued Sheba the son of Bichri.