1 Samuel 17:12-17

12Now David was son of a certain Ephrathite man of Beth-lehem of Judah, whose name was Jesse. He had eight sons and during the days of Saul the man was old, advanced in years among men.

13Now the three oldest sons of Jesse had already left and gone after Saul to the battle; the names of his three sons who went to the battle were Eliab the firstborn, and second to him Abinadab, and the third Shammah.

14David was the youngest. So the three oldest followed Saul.

15Now David would go back and forth from Saul to tending his father’s sheep by Beth-lehem.

16For forty days that Philistine would come out every morning and evening to present himself.

17Then Jesse said to his son David, “Take now, for your brothers, an ephah of this roasted grain and these ten loaves, and carry them quickly to the camp to your brothers.