1 Samuel 28:1-2

Revised Geneva Translation

28 Now at that time, the Philistines assembled their bands and army to fight with Israel. Therefore, Achish said to David, “Know assuredly that you shall go out with me to the battle, you and your men!”

² And David said to Achish, “Surely, you shall know what your servant can do.” And Achish said to David, “Surely, I will make you keeper of my head, forever.”