1 Samuel 17:48-50

As Goliath came near to attack him, David ran quickly to meet him. He took a stone from his bag, put it into his sling, and slung it. The stone hit the Philistine and went deep into his forehead, and Goliath fell facedown on the ground. So David defeated the Philistine with only a sling and a stone. He hit him and killed him. He did not even have a sword in his hand.