1 Samuel (Author Compiled by Isaiah from records of Samuel, David, Nathan, and Gad.)
17:51And David ran, and stood upon the Philistine, and took his sword, and drew it out of its sheath, and killed him completely, and cut off his head with it. And when the Philistines saw that their hero was dead, they fled.
Original from The Bible Foundation - bf.org. They claim public domain status for their original text.