Jether

Jether, also known as Ithra, was an Ishmaelite and the father of Amasa. Amasa was the son of Jether and Abigail, who was David's sister. Despite being David's nephew, Amasa sided with Absalom during his rebellion against David and was appointed as the commander of Absalom's army. After Absalom's death, David offered Amasa the position of commander over his army, replacing Joab. However, when Amasa failed to mobilize the troops quickly enough, David sent Abishai to pursue the rebel Sheba. Joab, who had been demoted, accompanied Abishai and took the opportunity to kill Amasa, viewing him as a threat to his position. The fact that Jether is described as an Ishmaelite suggests that he was not an Israelite, which may have contributed to Amasa's complex loyalties within David's family and kingdom.