'Eldest' in the Bible

Eventually, Isaac grew so old that he could not see. One day, he called his eldest son Esau. "My son," he called out to him.

These individuals also cast lots corresponding to their relatives, Aaron's descendants, in the presence of King David, Zadok, and Ahimelech, and in the presence of the heads of the ancestral households of the priests and of the descendants of Levi, and the eldest was treated as impartially as was the younger brother.