1 Samuel 17:18

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;

Now Saul, and they, and all the men of Israel, [were] in the valley of Elah, fighting with the Philistines.

And David rose up early in the morning, and left the sheep with a keeper, and took, and went, as Jesse had commanded him; and he came to the trench, as the host was going forth to the fight, and shouted for the battle.