Benjy returned from a visit to Israel with leftover shekels. He met his neighbor, Aharon, who was going there the following week.
“I have leftover shekels,” Benjy said. “Are you interested in purchasing them?”
“Sure, it will save me the need to exchange dollars when I arrive,” answered Aharon. “How many shekels do you have?”
“I have NIS3,000,” replied Benjy. “I’ll sell it for the current exchange rate (shaar yatzig).”
“Let me check how much that is,” said Aharon. “Give me a minute…”
Aharon checked the exchange rate. “3.769 shekels to the dollar,” he said. “That’s $796. We can round it off to $800.”
“I have the shekels at home,” Benjy said. “I can bring them over in the evening.”
“I won’t be home this evening,” Aharon said, “but I just came from the bank. I’ll give you the $800 now and you can leave the shekels with my family.” He gave Benjy $800.
When Benjy came home in the evening, he put the NIS3,000 in his wallet and headed over to Aharon’s house. On the way, he was accosted by armed thugs, who threatened him: “Your money or your life!”
Benjy took out his wallet and handed it to the thugs. They emptied the wallet of all the cash and ran off.
The following day, Benjy came over to Aharon and related what happened. “I was mugged on the way,” he said, “and the 3,000 shekels were stolen.”
“I’m terribly sorry to hear,” said Aharon empathically. “Thank G‑d you came out unscathed.”
Aharon’s son, who was learning Bava Metzia, overheard the conversation. “This raises a fascinating question!” he exclaimed. “Since my father already gave you dollars in exchange for the shekels, whose loss is it?”
Benjy and Aharon looked at each other. “Good question,” they pondered. “Let’s ask Rabbi Dayan!
“As you know, an act of acquisition (kinyan) is needed to finalize a transaction,” explained Rabbi Dayan. “According to most authorities, the Torah considers monetary payment as completing the transaction, but the Sages rendered the sale of movable items incomplete until a kinyan is made on the item itself, such as by picking it up.”
“Does that mean a person can simply renege after payment was made?” asked Benjy incredulously.
“No; although it is halachically possible, the Sages imposed a ban (mi shepara) upon whichever party reneges after payment was made,” replied Rabbi Dayan. “The One Who punished the generation of the deluge … should punish one who reneges on his word. Nonetheless, when the purchased item was lost, as in our case, the customer can renege without the associated ban” (C.M. 204:2).
“When exchanging currencies, though,” asked Aharon, “what is considered money and what is considered the item? Does giving dollars count as taking the item?”
“The currency that is more easily tendered is considered money, while the other currency is considered the item,” answered Rabbi Dayan. “The Mishnah (B.M. 44a) addresses coexisting currencies in gold, silver and copper coins. The silver coins were most easily tendered and hence considered money relative to the gold and copper currencies” (C.M. 203:4).
“I guess that solves our question,” said Benjy.
“The local currency is considered payment vis-à-vis the other currency,” continued Rabbi Dayan. “Thus, in Israel, giving dollars for shekels finalizes the transaction. However, in the United States, giving dollars is considered the money and does not finalize the transaction, so that the robbed shekels are Benjy’s loss.”