Between Pesach and Shavuos, Congregation Tiferes Banim distributed gedolim cards to the children who attended Avos U’banim (father-son learning).
David amassed almost a complete set and was missing only the card of the Chofetz Chaim. He had doubles of many other gedolim.
The final evening of the special program was on Shavuos night. David asked who might have a double of the Chofetz Chaim and found out that Boaz had.
After Shavuos, David approached Boaz. “I heard that you have a double of the Chofetz Chaim,” he said.
“Yes, I do,” replied Boaz. “I’m missing two other gedolim, though, to fill in my set.” He told David which cards he was missing.
“I have doubles of both,” offered David. “I’m happy to trade them for your extra Chofetz Chaim!”
“Deal!” exclaimed Boaz. “This way we can both have complete sets.”
“I have one of the two cards with me,” David said. “I’ll give it to you now. Later tonight I’ll stop by with the other card, and you’ll give me your Chofetz Chaim.”
Boaz went home; he prepared the extra Chofetz Chaim card on his dresser.
When David came by that evening, Boaz was shocked to discover that his two-year-old brother had somehow clambered onto the dresser. He had colored all over the card and even partially tore it.
“I’m sorry,” Boaz apologized to David, “but my baby brother ruined the Chofetz Chaim card…”
“Then give me back the card I gave you,” David said dejectedly.
“You already gave it to me,” replied Boaz. “It’s not my fault that the Chofetz Chaim card was ruined; it’s your loss! I’m willing, though, to give you another card from my doubles.”
“No,” said David. “Either give me your intact Chofetz Chaim card or give me back my card!”
The two approached Rabbi Dayan and asked, “Did Boaz already acquire the gedolim card he received from David?”
“Chazal derive kinyan chalipin (exchange) from a verse in Megillas Rus,” replied Rabbi Dayan. “It says: ‘Formerly this was done in Israel for redemption (geulah) and exchange (temurah), to validate any matter (l’kayeim kol davar): A person would take off his shoe and give to his fellow’ (4:7).
“Rabbeinu Tam explains that this verse refers to three forms of kinyan: ‘geulah’ is buying with payment; ‘temurah’ is barter of similarly valued items; ‘l’kayeim kol davar’ is kinyan sudar, a formal act of chalipin by handing a clothing item or other utensil (Tosafos B.M. 47a s.v. ge’ulah).
“The Mishna (Kiddushin 28a) teaches that when bartering items, such as a donkey for a cow, when the first party takes possession of the cow, the second party correspondingly acquires the donkey immediately, without need to make a separate kinyan on it, even if the donkey were to die before the second party took it (C.M. 203:1).
“However, the Gemara (B.M. 47a) teaches that if people barter a donkey for a cow and lamb, and the first party takes the cow, because this is only part of the barter, the other party does not thereby acquire the donkey. Moreover, the first party does not yet acquire the cow, even though he pulled it, so that if the donkey would die before the transaction was concluded, he must return the cow (C.M. 203:2; Prisha 203:2).
“Nonetheless, several Rishonim maintain that if the barter was for something that can easily be divided proportionally, the transaction is valid proportionally. For example, if the cow and lamb were exchanged for 30 bushels of wheat, when the first party took the cow, 20 bushels of wheat would correspondingly be transferred even if acquisition of the lamb was negated, unless the owner of the animals had indicated that he needed the entire quantity of wheat as a whole unit (C.M. 203:2; Rema 200:7; Pischei Choshen, Kinyanim 7:19).
“Thus, because the Chofetz Chaim card was bartered for two cards and Boaz took only one of them, the barter was not consummated,” concluded Rabbi Dayan. “The loss is not David’s, and Boaz must return the card that he already took. It would be mentchlich, though, to let Boaz keep it, in lieu of another card.”
Verdict: In barter, when one party takes what is forthcoming to him, the other party thereby acquires the corresponding item. However, taking only part of what is forthcoming does no consummate the barter, even for what was already taken.
