Rav Huna was a wealthy man who owned vast vineyards and employed many laborers to tend them. But he had a flaw. When the harvest was finished and the grapes had been pressed and the wine was flowing, Rav Huna refused to share any of it with the workers who had made it possible. They labored in the heat all day and received not a single cup.
Then came the catastrophe. Four hundred barrels of Rav Huna's wine — his entire stock, representing a fortune — turned sour. All at once, without explanation, every barrel curdled into vinegar. A year's worth of wealth, destroyed overnight.
Word spread quickly. The other rabbis came to see him, and they did not mince their words. "Examine your deeds," they told him. "This did not happen by accident."
Rav Huna was stricken. He looked inward and recognized his sin. He had been stingy with the very people who depended on him. He repented sincerely, vowing to treat his laborers with generosity going forward.
The moment his repentance was genuine, the vinegar turned back into wine. All four hundred barrels. The Talmud in Berakhot (5b) preserves two versions of what happened next — some say the wine was restored to its original quality, while others say the price of vinegar rose so sharply that Rav Huna was able to sell it for the same amount he would have earned from wine. Either way, the lesson was identical: God watches how the powerful treat the powerless, and He responds with precision. Withhold from your workers, and your wealth will sour. Repent, and even vinegar can become sweet again.