1 Samuel 14:13-15

13Then Jonathan climbed up on his hands and feet, his armor bearer following after him. The enemy fell before Jonathan [in combat], and his armor bearer killed some of them after him.

14That first slaughter which Jonathan and his armor bearer made was about twenty men within about half a [plow] furrow in a plot of land [the area of which a yoke of oxen could plow in a day].

15And there was trembling in the [Philistine] camp, in the field, and among all the people; even the garrison and the raiding party trembled [in fear], and the earth quaked and it became a trembling and terror from God.