1 Samuel 23:10

Destroy the city. There is no doubt that the inhabitants of Keilah were most grateful for David’s help, and for the moment probably gave no thought to any future involvements. Instead of remaining in the forest at Hareth, David found the city opened to him and his men, and the people doubtless did all they could to provide for the needs of such a large company. But news travels fast, and it was not long before Saul was notified of the details of the encounter with the Philistines, and the complexion of the situation changed overnight. The men of Keilah realized they would be forced to decide, on the one hand, between loyalty to Saul, with the retention of their status in Israel, and on the other hand, the implied rejection of Saul through their befriending of the outlawed David, with the consequent destruction of their city.

David revealed foresight in anticipating such a situation, but even with his long experience, he knew not which way to move. He had come to Hareth under divine guidance at precisely the time his presence was needed to save Keilah. Yet he knew if he remained within the walls, he would be fighting against the Lord’s anointed and initiating a civil revolution, which his very soul rebelled against.