1 Samuel 17:15-19

But David went and returned from Saul to feed his father's sheep at Beth-lehem. And the Philistine drew near morning and evening, and presented himself forty days. And Jesse said unto David his son, Take now for thy brethren an ephah of this parched corn, and these ten loaves, and run to the camp to thy brethren; and carry these ten cheeses unto the captain of their thousand, and look how thy brethren fare, and take their pledge. Now Saul, and they, and all the men of Israel, were in the valley of Elah, fighting with the Philistines.