Charles Ellicott Commentary 1 Samuel 28:5

"And when Saul saw the host of the Philistines, he was afraid, and his heart trembled greatly." — 1 Samuel 28:5 (ASV)

He was afraid. —There is no doubt that Saul was discouraged when he viewed the enemy’s ranks from the eminence of Gilboa. They were far more numerous than he had expected. But the real reason for his trembling must be sought in the awareness that God had forsaken him. Many of the well-known Israelite warriors had, during recent events, joined his dreaded rival, David, and David, he knew, was now the vassal of Achish, a Philistine king. We may imagine Saul, the forsaken of God, as he stood on the white chalk hill of Gilboa, gazing on the long lines of Philistine tents pitched on the opposite hill of Shunem, wondering if his old friend was there, with his mighty following, in the division of Gath.