A man was in the habit of rising from his meals without washing his hands properly. He left the table with crumbs and traces of the food on his fingers, indifferent to the small ritual the sages had built around the end of a meal.
One afternoon a stranger happened to observe him leaving a tavern, noted the exact food the man had eaten by the residue on his fingers, and filed the detail away. That evening the stranger went to the man's house while the husband was still away, knocked on the door, and told the wife that her husband had sent him. As proof, he recited exactly what her husband had eaten for lunch, down to the spices. The wife, unable to explain how he could know such a thing unless her husband had told him, believed the story. The stranger walked out with a valuable piece of household property she had handed him.
When the husband returned and learned what had happened, he flew into a rage. He could not see his own carelessness. He could only see what looked like his wife's betrayal. In a fury he killed her (Gaster, Exempla No. 159).
The sages tell the story as a warning about netilat yadayim, the washing of hands, which the tradition surrounds with the dignity of a sacred act. The lesson is not about a single ritual. It is about how a small neglect, like skipping a bowl of water, can leave a clue on the body that a dishonest person will know how to use. The man who thought he was saving a minute lost a wife and a soul.