KIDUSHIN WITH DEMEI ISUREI HANA'AH (Kidushin: Isurei Hana'ah: Chilufeihem)
56b (Mishnah): If one was Mekadesh a woman with any of the following, she is not Mekudeshes: Orlah, Kilayim of a vineyard...
If he sold any of these and was Mekadesh with the money, she is Mekudeshes.
58a - Question: What is the source of this?
Answer: It says about idolatry "v'Hayisa Cherem Kamohu" - whatever you are Mehaveh from (make, i.e. exchange for) it is (Asur b'Hana'ah,) like the idolatry. Regarding other Isurim, what one gets in exchange for them is permitted.
We do not learn from idolatry to other Isurim, for idolatry and Shemitah are Shnei Kesuvim (two verses, one of which could have been learned from the other). "Yovel Hi Kodesh Tihyeh Lachem" teaches that just like Kodesh forbids money exchanged for it, also Peros of (Yovel, which is like) Shemitah.
Nedarim 47a Question (Rami bar Chama): If one said 'this produce is forbidden to Ploni', may Ploni benefit from what it is exchanged for or what grows from it?
Answer (Mishnah): If he sold any of these and was Mekadesh with the money, she is Mekudeshes.
Rejection: Perhaps l'Chatchilah one may not exchange Isur, but b'Di'eved what it was exchanged for is permitted!
Chulin 4a (Beraisa): If Reuven (transgresses and) keeps Chametz during Pesach, immediately after Pesach, others may benefit from his Chametz, because he trades (his Chametz with that of Nochrim).
Avodah Zarah 62a (Mishnah): If a Nochri hired a Yisrael to work with Yayin Nesech, the wages are forbidden;
Suggestion: Since one may not benefit from it, also the wages are forbidden.
Rejection: It is forbidden to benefit from Orlah and Kilai ha'Kerem, yet if one sold them and was Mekadesh a woman with the money, she is Mekudeshes!
The Rif (Kidushin 23a) brings the Mishnah and the Gemara that learns that only idolatry and Shemitah forbids what is exchanged for them.
Rambam (Hilchos Ishus 5:2): If he transgressed and sold something Asur b'Hana'ah and was Mekadesh with the money, she is Mekudeshes. The only exception is idolatry. If he sold idolatry and was Mekadesh with the money she is not Mekudeshes, because money received for idolatry is forbidden like idolatry.
Rosh (Kidushin 2:31): Rashi (Avodah Zarah 54b DH li'M'utei) says that one who sold Isurei Hana'ah may not benefit from the money, but if he was Mekadesh a woman with the money, she may benefit from it. For her, it is Demei Orlah. Even though he benefited from the money, i.e. he was Mekadesh a woman with it, Chachamim were not so stringent about Kidushin. They forbade buying with the money only things like Kelim and Peros, which are blatant. Alternatively, they were lenient about Kidushin for the sake of Peru u'Rvu.
Rosh: Rashi did not need to say so. L'Chatchilah, one may not be Mekadesh a woman with the money! B'Di'eved, she is Mekudeshes. Similarly, one may not buy Peros or Kelim with Demei Isurei Hana'ah. B'Di'eved, if one bought them, Chachamim did not forbid them. Rashi agrees that mid'Oraisa, he may use the money, for these Isurim do not transfer Isur to what they are exchanged for. Chulin 4a supports this. If one keeps Chametz during Pesach, right after Pesach others may benefit from his Chametz, for he trades his Chametz with that of Nochrim, to lighten his Isur. If what it is traded for were Asur mid'Oraisa, trading would not help! Rashi explained there that the Nochri's Chametz is also forbidden, for it was bought with Isurei Hana'ah, but it is a lighter Isur. Rashi learned from Nedarim that there is an Isur mid'Rabanan. We brought the Mishnah to prove that if Peros were forbidden by Konam, Chilufeihem are permitted. We rejected this, for perhaps l'Chatchilah Chilufeihem are forbidden.
Question: How can the money be Mekadesh? Since it was given for Isurei Hana'ah (which cannot be sold), the money must be returned to the buyer!
Answer (Rosh): The case is, a Nochri bought it. Alternatively, a Yisrael bought, and he knew that it is Isurei Hana'ah. The money was a gift. The Yerushalmi asked that this is Kidushin with Gezel, which does not work! It gives these answers that I gave. I would have said that it is not Gezel. The money was paid to buy it and the seller acquired the money. Even though it is a Mekach Ta'os and he must refund the money, the seller owns the coins he received.
Mishneh l'Melech (Hilchos Ishus 5:7 DH ha'Klal): The Rosh accepted the Yerushalmi's ruling that it is Gezel. The Bavli does not argue. However, perhaps it is Gezel only regarding Isurei Hana'ah, which has no value, but not if it as a Mekach Ta'os because the seller covered up a Mum in the item.
Question: If so, how did the Gemara (Avodah Zarah 62a) use the Mishnah to prove that some benefits that come from Isurei Hana'ah are permitted?
Answer (Rosh): We thought that all benefits from Isurei Hana'ah are forbidden to everyone. The Mishnah disproves this (if the woman were forbidden to benefit, the Kidushin was worth nothing for her, and she would not be Mekudeshes).
Rosh (Nedarim 47b DH Dilma): The Gemara asked whether l'Chatchilah one may exchange Isurei Hana'ah to benefit from the money.
Question (Mishneh l'Melech Hilchos Ishus 5:1 DH v'Ra'isi leha'Rosh Zal): Surely, the Gemara knew that l'Chatchilah one may not exchange Isurei Hana'ah and benefit from the money! The Torah needed to permit selling a Neveilah. This shows that l'Chatchilah, one may not sell other Isurim (that are Isurei Hana'ah). Also, if one may sell it l'Chatchilah, Chametz forbidden during Pesach is worth money. Why is one who stole it exempt?
Shulchan Aruch (EH 28:22): If he transgressed and sold an Isurei Hana'ah (other than idolatry) and was Mekadesh with the money, she is Mekudeshes. If the buyer was a Yisrael who did not know that it is Asur, she is Safek Mekudeshes.
Beis Shmuel (57): L'Chatchilah, he may not be Mekadesh with (or get other benefit from) the money, even though the Isur did not transfer to the money.
Question (Beis Shmuel 58): The Rosh says that if the buyer knew that it is Asur, the money was a gift. Why is this different than one who buys a field that he knows does not belong to the seller? There, we say that the money is a deposit! We say that one who was Mekadesh his sister intended that the money is a gift, but we do not say that one gives (in similar cases) to others!
Answer (Eretz Tzvi 4, brought in Rosh Pinah Shulchan Aruch): Perhaps Isurei Hana'ah are different, for the buyer wanted them for a Choleh!