2 Samuel 17:25
25 Now Absalom had set tAmasa over the army instead of Joab. Amasa was the son of a man named Ithra the Ishmaelite,1 who had married Abigal the daughter of Nahash, sister of Zeruiah, Joab’s mother.
2 Samuel 18:2
2 And David sent out the army, one third under the command of Joab, one third under the command of xAbishai the son of Zeruiah, Joab’s brother, and one third under the command of yIttai the Gittite. And the king said to the men, “I myself will also go out with you.”