1 Samuel (Author Compiled by Isaiah from records of Samuel, David, Nathan, and Gad.)
17:39And David girded his sword upon his armour, and he assayed to go; for he had not proved it. And David said unto Saul, I cannot go with these; for I have not proved them. And David put them off him.
Original from The Bible Foundation - bf.org. They claim public domain status for their original text.