1 Chronicles (Author Compiled by Isaiah and Ezra from records of Nathan, Gad, Iddo, Ahijah, Jehu and others.)
11:15And three of the thirty heads go down on the rock unto David, unto the cave of Adullam, and the host of the Philistines is encamping in the valley of Rephaim,
Original from The Bible Foundation - bf.org. They claim public domain status for their original text.