II Samuel 20:8

8 While they were at the great rock in Gibeon, Amasa came to meet them. Joab was wearing his military tunic, and strapped over it at his waist was a belt with a dagger in its sheath. As he stepped forward, it dropped out of its sheath.

8 When they were at the great stone which is in Gibeon, Amasa came to meet them. And Joab was girded with his apparel of war that he had put on, and thereon was a girdle with a sword fastened upon his loins in the sheath thereof; and as he went forth it fell out.