Abraham had eight sons: Ishmael from Hagar, Isaac from Sarah, and six sons — Zimran, Jokshan, Medan, Midian, Ishbak, and Shuah — all from Keturah, his second wife after Sarah’s death. There is a blessing for all of Abraham’s children, but the special, everlasting covenant is only for Isaac because this promise was made to Sarah’s son, and she had only one son.