1 Samuel 17:15-19

but David went back and forth from Saul to tend his father’s sheep at Bethlehem. For forty days the Philistine came forward every morning and evening and took his stand. Now Jesse said to his son David, “Take this ephah of roasted grain and these ten loaves of bread for your brothers and hurry to their camp. Take along these ten cheeses to the commander of their unit. See how your brothers are and bring back some assurance from them. They are with Saul and all the men of Israel in the Valley of Elah, fighting against the Philistines.”