1 Chronicles (Author Compiled by Isaiah and Ezra from records of Nathan, Gad, Iddo, Ahijah, Jehu and others.)
Chapter 11
15Now three of the thirty captains went down to the rock to David, into the cave of Adullam; and the host of the Philistines encamped in the valley of Rephaim.
Original from The Bible Foundation - bf.org. They claim public domain status for their original text.