1 Samuel 14:10-14

But if they say thus, Come up unto us; then we will go up: for the LORD hath delivered them into our hand: and this shall be a sign unto us.

And both of them discovered themselves unto the garrison of the Philistines: and the Philistines said, Behold, the Hebrews come forth out of the holes where they had hid themselves.

And the men of the garrison answered Jonathan and his armourbearer, and said, Come up to us, and we will shew you a thing. And Jonathan said unto his armourbearer, Come up after me: for the LORD hath delivered them into the hand of Israel.

And Jonathan climbed up upon his hands and upon his feet, and his armourbearer after him: and they fell before Jonathan; and his armourbearer slew after him.

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.