1 Samuel (Author Compiled by Isaiah from records of Samuel, David, Nathan, and Gad.)
17:39And David girded his sword upon his dress, and endeavoured to go; for he had not yet tried it. And David said to Saul, I cannot go in these; for I have never tried them. And David put them off him.
Original from The Bible Foundation - bf.org. They claim public domain status for their original text.