1 Samuel 14:15
And there was trembling in the host, in the field, and among all the people: the garrison, and the spoilers, they also trembled, and the earth quaked: so it was a very great trembling. And there was trembling in the host, in the field, and among all the people: the garrison, and the spoilers, they also trembled, and the earth quaked: so it was a very great trembling.
God brought Israel to a crisis to rebuke the perversity of Saul and to teach humility and faith. Because of Saul's sin in his presumptuous offering, He would not give him the honor of vanquishing the Philistines. He chose Jonathan, the king's son, a man who feared the Lord, as the instrument to deliver Israel. Moved by a divine impulse, Jonathan with his armor-bearer, also a man of faith and prayer, secretly withdrew from camp, prayed to the Guide of their fathers and agreed upon a sign to determine how to proceed. They threaded the gorge under cover of cliff and ridges, took the Philistine taunt and challenge as evidence the Lord would prosper their undertaking, and climbed by a secret and difficult path to a summit deemed inaccessible and not strongly guarded. There they penetrated the enemy camp and slew the sentinels who, overcome with surprise and fear, offered no resistance, beginning the very great trembling in host, field and garrison.
The very great trembling seized the whole Philistine force — the host, those in the field, the garrison, and the raiding parties. The quaking of the earth was a miraculous earthquake, caused by the armies of heaven working with Jonathan and his armor-bearer as they attacked the outpost, which added to the Philistines' terror and intensified their fear and confusion.
The Philistines saw the effects of the attack as if a great host or large force were against them. The trembling and confusion were signs of divine aid, and the Philistines recognized that the Lord was acting for Israel and delivering Israel. In their fear and panic they mistook their own soldiers for enemies and turned against one another, fighting and killing one another, which turned the battle in Israel's favor. Israel's deliverance came through God's power, not its own strength or merit.