Albert Barnes Commentary 1 Samuel 14:12

"And the men of the garrison answered Jonathan and his armorbearer, and said, Come up to us, and we will show you a thing. And Jonathan said unto his armorbearer, Come up after me; for Jehovah hath delivered them into the hand of Israel." — 1 Samuel 14:12 (ASV)

We will show you a thing — This was said mockingly.