1 Samuel 17:20-22

20Early in the morning David left the flock in the care of a shepherd, loaded up and set out, as Jesse had directed. He reached the camp as the army was going out to its battle positions, shouting the war cry. 21Israel and the Philistines were drawing up their lines facing each other. 22David left his things with the keeper of supplies, ran to the battle lines and asked his brothers how they were.