1 Samuel 17:15-19

but David went back and forth from Saul to tend his father’s flock at Bethlehem. The Philistine came forward morning and evening for forty days and took his stand. Then Jesse said to David his son, “Take now for your brothers an ephah of this roasted grain and these ten loaves and run to the camp to your brothers. Bring also these ten cuts of cheese to the commander of their thousand, and look into the welfare of your brothers, and bring back news of them. For Saul and they and all the men of Israel are in the valley of Elah, fighting with the Philistines.”