Reference: I explained R. Tam's ruling in Yevamos (39b DH Amar. The Halachah follows Aba Sha'ul, like the Stam Mishnah here.)

Reference: In Erchin (27a) it gives a different reason. The owner has precedence, because he adds a Chomesh. There it challenges this, and answers.

Implied question: [It should suffice to] teach that he acquired!

Answer: It needs to teach that it is obligated in Bechorah, lest one say that he acquired amidst Safek, or mid'Rabanan. [Through teaching v'Chayeves bi'Vchorah,] we learn that he totally acquired.

Explanation: [Land is acquired through money, a document or Chazakah] when one acquires from a Yisrael. The same applies to an Eved Kena'ani, when one buys him from a Yisrael;

However, for a Nochri, it is unreasonable that a document will help, for Kinyan through a document does not apply to a Nochri, like we say in Bava Basra (54b), that a Nochri [seller], once coins come to his hand, he removes himself [from owning the property], but a Yisrael does not acquire until the document comes to his hand.

Question: Perhaps one acquires from a Nochri through a document or Chazakah, for also Chazakah applies to Metaltelim, if he did any Tikun, similar to locking, fencing or breaching in land!

Answer: These two Kinyanim are available and applicable - this [applies to] the seller, and this to the buyer. This one receives the coins, and this one pulls the item to himself (his Reshus).

And similarly according to R. Yochanan below (13b) we expound oppositely. "To Amisecha (your fellow Yisrael, the Kinyan is) with money, but to a Nochri, with Meshichah."

Question: What is the source that [Kesef and Meshichah] are considered a Kinyan at all, that we establish the Kinyanim of the verses to discuss them?

Answer: We find that money acquires elsewhere regarding land and Hekdesh, and Meshichah acquires a Metzi'ah and Hefker.

Question: Perhaps [a Nochri's Kinyan] is Chalipin, for he is Makneh his property, like he expounds in Kidushin (8a) "mi'Kesef Miknaso" - [an Eved Ivri] is acquired through Kesef, and not through the law of (Kinyan done with) grain and Kelim. What is [this Kinyan]? It is Chalipin!

And the verse discusses an Eved Ivri sold to a Nochri. This implies that a Nochri acquires other things, e.g. Metaltelim, through Chalipin!

Answer #1: If we do not find Kesef of Meshichah in [Kinyanim of] a Nochri, we would not establish the verse for Chalipin!

Answer #2: It says that a Nochri acquires through one [Kinyan] - this does not discuss Chalipin, which is the same for a Nochri and Yisrael, rather, a new Kinyan, e.g. Kesef or Meshichah. (It is new, i.e. it does not apply to Yisrael.)

Explanation: If a Nochri acquires a Yisrael's body through money [all the more so, his property]!

Inference: Since it did not ask here "if so, even through a document or Chazakah [a Nochri should acquires a Yisrael's property]", like it asked above, this proves that R. Tam is correct. He explained in Kidushin (14b, regarding) "we find an Eved Ivri sold to a Nochri [is acquired through Kesef], for his entire Kinyan is Kesef"...

Explanation #1 (R. Tam): I.e. a Nochri acquires an Eved Ivri only through Kesef, like it is written "mi'Kesef Miknaso", and not through a document or Chazakah, like is proven here.

Explanation #2 (Rashi there): For everything, a Nochri's Kinyan is Kesef, like we expound here "to Amisecha with Meshichah, but to a Nochri, with Kesef."

Question: That Drashah is according to Reish Lakish, and the Halachah follows R. Yochanan!

Question: Still, a Nochri acquires a Yisrael through Chazakah, like it says in Gitin (38a) 'what is the source that a Nochri acquires a Yisrael through Chazakah? It says "va'Yoshb Mimenu Shevi"'!

Answer: That Chazakah is conquest in war, and the same applies to his property, like it says in Chulin (60b) "Amon and Mo'av were permitted through Sichon." (Yisrael were forbidden to take their land. Since Sichon conquered them, it was no longer considered theirs. "His property" connotes a Yisrael's, but Tosfos brings a proof that a Nochri acquires a Nochri's! Perhaps Tosfos holds that it is unreasonable to distinguish.

Explanation #1 (Rashi): It says about Hekdesh 'v'Nasan ha'Kesef v'Kam Lo', and we learn a person from Hekdesh.

Question: According to Reish Lakish, who says that Meshichah is explicit in the Torah, he should learn that Kesef acquires for people, like regarding Hekdesh, and Meshichah acquires also for Hekdesh, like for people!

Answer #1 (R. Yehudah bar Nasan): Meshichah does not apply to Hekdesh, for wherever it is, it is in Hash-m's storehouse. Therefore, Kesef applies to Hekdesh more than to a person. And a person, who can do Meshichah, he does not have another Kinyan.

Answer #2 (Ri): He properly learns from verses. We expound "to Amisecha with Meshichah, but to a Nochri, with Kesef." And since a Nochri has one [Kinyan], also a Yisrael has one, for they are learned from each other.

Implied suggestion: Perhaps a Nochri acquires with this or this (Kesef or Meshichah), and similarly a Yisrael!

Rejection: If so, they would be the same. ("To Amisecha..." implies that they are different.)

Implied question: If you will say that Chalipin acquires for a Yisrael, but not for a Nochri, unlike I explained above (13a DH Eima, you could say that they are the same regarding Kesef and Meshichah, and different regarding Chalipin)!

Answer: We can say that the verse discusses only common, available Kinyanim such as Kesef and Meshichah. Regarding these, we learn a Yisrael and a Nochri from each other.

Explanation #2 (Tosfos' Rebbi): R. Yochanan holds that coins acquire due to the verse itself "Oh Kano mi'Yad Amisecha." Stam Kinyan of the Torah is coins, like it says "Sados ba'Kesef Yiknu", and "mi'Kesef Miknaso."

Explanation #1 (Rashi): This is an argument in Bava Kama (113b).

Objection: The entire Sugya there proves that it is forbidden! They argue about uprooting his loan (that is owed to him, but no one permits stealing from him).

Explanation #2: However, in Sanhedrin (57a) a Beraisa teaches "robbery and theft, and also Eshes Yefas To'ar (if she is married, taking her is like stealing from her husband) - it is permitted for a Yisrael [to take] from a Kena'ani."

And also in Bava Metzi'a (111b), it says "one permits Gezel of (from) a Kena'ani, and one permits Oshko (withholding his wages) regarding "Re'echa" and "Achicha".

Question: How is Gezel Kena'ani permitted? It says "v'Chishev Im Konehu" (one who redeems an Eved Ivri from a Nochri must pay the proper amount)!

(Do not say that it discusses when the Nochrim are in control, but when Yisrael are in control, Gezel is permitted.) The verse discusses when [the Nochri] is under your control. If he is not under your control, will he agree to [let you redeem him] based on the number of years until Yovel?! (He will demand the full amount he paid, and perhaps even more!)

Answer: When there is Chilul Hash-m, surely [Gezel Nochri] is forbidden. It is permitted [according to one opinion] when one can evade (blatant robbery), and he steals through [improper] claims or various ways.

Question: In Avodah Zarah (71b) it brings this Beraisa to infer oppositely from the Reisha!

It says "if you will say that Meshichah acquires regarding a Nochri, why may he return?!" (The Yisrael already acquired the idolatry. Returning it is like selling it back!)

Answer (Ri): The Makshan holds here and there that both of them are needed regarding a Nochri, Meshichah and coins.

Support: Now [we understand] why [the Makshan] was content here and there [and did not ask a contradiction between] the Reisha and the Seifa.

Question: There is a [curse] Mi she'Para [that he must accept if he retracts]!

Answer #1: He accepted to act according to Dinei (the laws of) Yisrael. Mi she'Para is not a Din.

Answer #2: We can answer like R. Tam explained in Bava Metzi'a 47b. Mi she'Para applies [to one who retracts due] to a change in price, but not in a case when he would totally lose.

Implied question: Below (14a DH v'Hani), I will explain that if Mechusar Emanah applied to [retracting from] mere words, it would be forbidden [to return] because it looks like idolatry in a Yisrael's hand (he acquired, and now he sells it back)!

Answer #1: Abaye is not concerned for what looks like idolatry in a Yisrael's hand.

Answer #2: Here it does not look at all [like idolatry in a Yisrael's hand]. Since there is no Mi she'Para, there is not Mechusar Emanah regarding a Nochri, just like regarding a Yisrael.

Implied question: We do not say so in other cases of Mekach Ta'os!

Answer: One who buys pieces of silver from a Nochri is different. It should cross his mind more, perhaps there is idolatry among them.

Pesak: R. Tam normally rules like R. Yochanan, that mid'Oraisa coins acquire, because Rava rules like him in Yevamos (37a) in every place that he argues with Reish Lakish, except for three (and this is not one of the exceptions).

Question: Here it is difficult, for Rav Ashi, who was after Rava, holds like Reish Lakish that Meshichah is explicit in the Torah!

Since he said that Meshichah of a Nochri does not acquire, this shows that we expound "to Amisecha with Meshichah, but to a Nochri, with Kesef";

If [he held] like R. Yochanan, [this cannot be, for R. Yochanan] said that "to Amisecha with Kesef, but to a Nochri, with Meshichah"!

Answer #1: Rav Ashi here retracted to [hold like] Ameimar, like is proven in Avodah Zarah (71a) regarding Ameimar's teaching that Meshichah of a Nochri acquires;

Citation (71a) Support: Persians send Pardashnei (gifts to friends, or samples of grain to prospective buyers), and they do not retract.

Ravina and Rav Ashi debate the matter there, and at the end of the Sugya we conclude "this shows that Meshichah of Nochrim acquires."

Support: Also, Ravina challenged Rav Ashi there from R. Yochanan's teaching about a Ben Noach, and Rav Ashi did not answer "R. Yochanan teaches like he taught elsewhere, that mid'Oraisa coins acquire, and I hold like Reish Lakish!"