1 Samuel 14:14-15

(14) And that first slaughter, which Jonathan and his armourbearer made, was about twenty men, within as it were an half acre of land, which a yoke of oxen might plow. (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.

It should seem, that a similar effect, like that which the Lord wrought in the host of Midian, must have been induced, to cause this great consternation, and trembling. The thing was of the Lord. Judges 7:22.