2 Samuel 17:25-26

25Absalom had appointed Amasa as commander of his army, replacing Joab, who had been commander under David. (Amasa was Joab’s cousin. His father was Jether, an Ishmaelite. His mother, Abigail daughter of Nahash, was the sister of Joab’s mother, Zeruiah.)

26Absalom and the Israelite army set up camp in the land of Gilead.