2 Samuel 20:6-8

6 So the king said to Abishai, "Sheba will give us more trouble than Absalom. Take my men and go after him, or else he may occupy some fortified towns and escape from us."

7 So Joab's men, the royal bodyguards, and all the other soldiers left Jerusalem with Abishai to go after Sheba.

8 When they reached the large rock at Gibeon, Amasa met them. Joab was dressed for battle, with a sword in its sheath fastened to his belt. As he came forward, the sword fell out.