'Eldest' in the Bible

and the three eldest sons of Jesse go, they have gone after Saul to battle; and the name of his three sons who have gone into battle are Eliab the first-born, and his second Abinadab, and the third Shammah.

And David is the youngest, and the three eldest have gone after Saul,

And Eliab, his eldest brother, heareth when he speaketh unto the men, and the anger of Eliab burneth against David, and he saith, 'Why is this -- thou hast come down! and to whom hast thou left those few sheep in the wilderness? I have known thy pride, and the evil of thy heart -- for, to see the battle thou hast come down.'