A man entrusted a single dinar to a woman for safekeeping. She placed the coin in a jar of flour — a common hiding place in the ancient world — and promptly forgot about it. Days later, she baked bread from that flour, unknowingly baking the dinar into a loaf.
A poor man came to her door begging for food. She gave him the loaf — dinar and all — never realizing what was hidden inside.
When the owner of the dinar came to reclaim his money, the woman searched everywhere. The coin was gone. She had no idea what had happened to it. In her distress, she swore a terrible oath: "May I lose one of my children to poison if I have made any use of your money."
She had spoken the truth — she had not used the money for herself. She had given it away, unknowingly, in an act of charity. But the oath was sworn, and oaths carry their own terrible weight. One of her children died, exactly as she had invoked.
The sages were shaken by this story. The woman was innocent. She had not stolen. She had not lied. She had, in fact, performed an accidental mitzvah by giving the coin to a poor man. Yet the oath destroyed her child.
The lesson was carved into the consciousness of every subsequent generation: do not take the name of God in vain, even in a true oath. Do not invoke God as witness to your innocence, because the forces unleashed by an oath do not discriminate between the guilty and the innocent. The words themselves have power. Once spoken in God's name, they cannot be recalled — and their consequences are irreversible.