1Sam 17:50-51

50So David prevailed over the Philistine with a sling and a stone, striking down the Philistine and killing him; there was no sword in David's hand.51Then David ran and stood over the Philistine; he grasped his sword, drew it out of its sheath, and killed him; then he cut off his head with it. When the Philistines saw that their champion was dead, they fled.