2 Samuel 17:25

25Absalom put Amasa in command of the army instead of Joab. Now Amasa was the son of a man named 17:25 This man was also known as Jether the Ishmaelite (1 Chr 2:17).Ithra the Israelite, who had married Abigail the daughter of Nahash, [the half-sister of David and] the sister of Zeruiah, Joab’s mother.