1 Samuel 17:48-52

Then it happened when the Philistine rose and came and drew near to meet David, that David ran quickly toward the battle line to meet the Philistine. And David put his hand into his bag and took from it a stone and slung it, and struck the Philistine on his forehead. And the stone sank into his forehead, so that he fell on his face to the ground. Thus David prevailed over the Philistine with a sling and a stone, and he struck the Philistine and killed him; but there was no sword in David’s hand. Then David ran and stood over the Philistine and took his sword and drew it out of its sheath and killed him, and cut off his head with it. When the Philistines saw that their champion was dead, they fled. The men of Israel and Judah arose and shouted and pursued the Philistines as far as the valley, and to the gates of Ekron. And the slain Philistines lay along the way to Shaaraim, even to Gath and Ekron.