A shepherd boy, tending his flock near a village, often amused himself by crying out, "Wolf! Wolf!" His trick succeeded two or three times. Each time, the whole village ran to help him, only to be laughed at for their trouble.
One day, a wolf truly came. The boy cried out in earnest. But his neighbors, thinking he was up to his old tricks, paid no heed to his cries. The wolf devoured the sheep.
Thus, the boy learned too late that liars are not believed even when they tell the truth.