Adam Clarke on 1 Samuel 14:15

There was trembling in the host - They were terrified and panic-struck; the people in general round about, those in the garrison, the spoilers, and the whole country, were struck with terror; the commotion was universal and most extraordinary. The trembling of the earth is probably not to be taken literally, but as a metaphor for a great commotion in the country, though God might have interposed in an extraordinary manner, and produced a real earthquake; but their being panic-struck was sufficient to produce all the requisite confusion and dismay.