1 Samuel (Author Compiled by Isaiah from records of Samuel, David, Nathan, and Gad.)
29:8And David said to Achish, But what have I done? and what hast thou found in thy servant so long as I have been with thee to this day, that I should not go and fight against the enemies of my lord the king?
Original from The Bible Foundation - bf.org. They claim public domain status for their original text.