1 Samuel 17:48-51
New International Version
48 As the Philistine moved closer to attack him, David ran quickly toward the battle line to meet him. 49 Reaching into his bag and taking out a stone, he slung it and struck the Philistine on the forehead. The stone sank into his forehead, and he fell facedown on the ground.
50 So David triumphed over the Philistine with a sling(A) and a stone; without a sword in his hand he struck down the Philistine and killed him.
When the Philistines saw that their hero was dead, they turned and ran.