1 Samuel 17:48-51

48The Philistine drew steadily closer to David to attack him, while David quickly ran toward the battle line to attack the Philistine.

49David reached his hand into the bag and took out a stone. He slung it, striking the Philistine on the forehead. The stone sank deeply into his forehead, and he fell down with his face to the ground.

50David prevailed over the Philistine with just the sling and the stone. He struck down the Philistine and killed him. David did not even have a sword in his hand.

51David ran and stood over the Philistine. He grabbed Goliath’s sword, drew it from its sheath, killed him, and cut off his head with it. When the Philistines saw their champion was dead, they ran away.