1 Samuel 28:1-5

Now it came about in those days that the Philistines gathered their armed camps for war, to fight against Israel. And Achish said to David, “Know for certain that you will go out with me in the camp, you and your men.”

David said to Achish, “Very well, you will learn what your servant can do.” So Achish said to David, “Then I will assuredly make you my bodyguard for life!”

Now Samuel was dead, and all Israel had mourned him and buried him in Ramah, his own city. And Saul had removed the mediums and spiritists from the land.

So the Philistines assembled and came and camped in Shunem; and Saul gathered all Israel together, and they camped in Gilboa.

When Saul saw the camp of the Philistines, he was afraid and his heart trembled greatly.