What does 1 Samuel 16:11 mean?

Samuel asked Jesse, 'Are these all your sons?' Jesse said, 'Well, there’s still the youngest, but he’s out taking care of the sheep.' Samuel said, 'Send for him. We’re not sitting down to eat until he gets here.' 1 Samuel 16:11 - Modern Text Bible

(Samuel insists on seeing every son, and Jesse mentions the youngest, who’s been overlooked and left working in the fields.)