תְּנַן: הַזָּהָב קוֹנֶה אֶת הַכֶּסֶף, מַאי לָאו בַּחֲלִיפִין, וּשְׁמַע מִינַּהּ מַטְבֵּעַ נַעֲשֶׂה חֲלִיפִין? לֹא, בְּדָמִים. אִי הָכִי הַזָּהָב קוֹנֶה אֶת הַכֶּסֶף, מְחַיֵּיב מִבְּעֵי לֵיהּ! תְּנִי: הַזָּהָב מְחַיֵּיב.
We learned in the mishna: When one party takes possession of the gold coins the other party acquires the silver coins. What, is the reference not to a case where the gold coins were given in order to acquire the silver coins by means of exchange, and therefore one can learn from it that a coin can be an item used to effect exchange? The Gemara rejects this proof: No, it is referring to a standard purchase effected by means of giving money. The Gemara raises a difficulty: If so, the language of the mishna is imprecise, as what is the meaning of: When one party takes possession of the gold coins, the other party acquires the silver coins? It should have stated: When one party takes possession of the gold coins, it obligates him to give the silver coins. The Gemara answers: Emend the text and teach: When one party takes possession of the gold coins, it obligates him to give the silver coins.
