A gypsy fortune-teller once told a man of meager means: “Be careful! A very rich man named Joseph, who always honors the Sabbath day, will someday own all of your possessions!”
To prevent the fortune-teller’s prediction, the man devised a plan. He sold everything he owned, and with the money, he bought a precious gem. To keep his valuable new possession in safety, he hid it in the turban that he never took off his head.
One day while the man was crossing a bridge, a strong wind blew off his turban, and it fell into the stream below. Just then a fish swam by and swallowed the hidden jewel. The same fish was caught and sold on the market as the freshest and best catch of the day. “Who will buy this fine fish?” the villagers cried.
“Go to Joseph,” someone suggested. “Certainly he will purchase this beautiful, fresh fish for the Sabbath.”
Joseph was delighted to buy the fish because he always wanted the best and the freshest fish for the Sabbath. When he cut the fish open, to his great surprise, he found the precious gem inside and later sold it for a large sum of money.
The story about Joseph and the fish spread from village to village. In response, a wise old sage said, “Whosoever spends for the Sabbath, the Sabbath has a way to pay him back.”
Talmudic Source: Shabbat 119a