1 Samuel 17:49-51
17:49 David 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.
17:50 David 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.
17:51 David 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.