1 Samuel 17:48-52

When the Philistine rose and came forward to meet David, David ran quickly toward the battle line to meet the Philistine. David put his hand into his bag and took out a stone and slung it, and it struck the Philistine on his forehead. The stone penetrated his forehead, and he fell face down on the ground. So David triumphed over the Philistine with a sling and a stone, and he struck down the Philistine and killed him; but there was no sword in David’s hand. So he ran and stood over the Philistine, grasped 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 [mighty] champion was dead, they fled. The men of Israel and Judah stood with a shout and pursued the Philistines as far as the entrance to the valley and the gates of Ekron. And the [fatally] wounded Philistines fell along the way to Shaaraim, even as far as Gath and Ekron.