I Samuel 17:41-51

41. Meanwhile, the Philistine, with his shield bearer in front of him, kept coming closer to David.
42. He looked David over and saw that he was only a boy, ruddy and handsome, and he despised him.
43. He said to David, "Am I a dog, that you come at me with sticks?" And the Philistine cursed David by his gods.
44. "Come here," he said, "and I'll give your flesh to the birds of the air and the beasts of the field!"
45. David said to the Philistine, "You come against me with sword and spear and javelin, but I come against you in the name of the LORD Almighty, the God of the armies of Israel, whom you have defied.
46. This day the LORD will hand you over to me, and I'll strike you down and cut off your head. Today I will give the carcasses of the Philistine army to the birds of the air and the beasts of the earth, and the whole world will know that there is a God in Israel.
47. All those gathered here will know that it is not by sword or spear that the LORD saves; for the battle is the LORD's, and he will give all of you into our hands."
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 and a stone; without a sword in his hand he struck down the Philistine and killed him.
51. David ran and stood over him. He took hold of the Philistine's sword and drew it from the scabbard. After he killed him, he cut off his head with the sword. When the Philistines saw that their hero was dead, they turned and ran.