The Old Woman and the Doctor
An old woman whose eyesight was failing hired a doctor to cure her illness. She promised to pay the doctor a large fee if she recovered, but nothing if she did not. The malicious doctor stole a valuable item from the house every time he visited to examine her eyes. When the treatment ended, no valuable item was left un-stolen in the woman's house.
When the doctor fully opened her eyes and demanded the promised fee, the woman refused to pay. Going to court, the doctor complained about the woman; the judge asked her why she did not pay. The woman said "Even if my eyes were weak before, I could see my things; now I see no belongings at all." The doctor had cured her eyes, but thereby provided proof of his own theft.
Whoever does evil falls into their own trap. The cheater falls into the pit they dug. Dishonesty comes to light sooner or later. Greed for unjust gain leaves one disappointed.
The reward of theft does not go unpunished. One who falls into their own trap cannot complain. Lies have short legs.