1 Samuel 7:7

And when the Philistines heard that the children of Israel were
gathered together to Mizpeh
Not knowing it was upon a religious account; but supposing they met to form schemes and measures to cast off their yoke, and deliver themselves out of their hands; and were preparing to take up arms, and fall upon them:

the lords of the Philistines went up against Israel;
with forces out of their several principalities united to fight with them; judging it advisable to lose no time, but attack them before they were well prepared and provided to defend themselves:

and when the children of Israel heard it, they were afraid of the
Philistines;
because they were unarmed, and not at all prepared for war, and having no expectation of it.