Explanation #1: 'For plowing', Rashi explains. And 'that it is Asur be'Hana'ah', he says, to explain the Seifa 'mi'she'Nigmar Dino, Eino Machur'.

Explanation #2: And even according to Rabeinu Tam, who explains that it does not become Asur be'Hana'ah during its lifetime, it is nevertheless forbidden to retain it due to the Isur of 'causing pain by delaying its death.

Explanation #3: In one of the versions of Rashi's commentary, Rashi ascribes 'Machro Machur' to the sellers claim to the purchaser that 'You should have Shechted it, since you knew that it killed a person, in which case you caused your own loss, and it is not a false sale!

Question: In that case, why does the Seifa say rule 'mi'she'Nignar Dina, Eino Machur'? Presumably there too, the purchaser knew that the ox had killed a person and that its Din had been concluded, similar to the Reisha; If so, the money ought to be a gift ...

Precedent: ... like the case of someone who betroths his sister?

Answer: Because not everybody is conversant in the Din of an ox that needs to be stoned; they think that one is permitted to retain it, in order to work with it, or even to Shecht it.

Explanation #1: Rashi explains that this is because we Pasken in 'ha'Gozel Eitzim' (later, on Daf 98b) that, according to the Rabanan, he can say "Harei she'Lecha Lefanecha!'

Explanation #1 (cont.): Since we learned in a Beraisa that if someone steals Chametz and Pesaxh passes or if he steals an ox and returns it before its Din has been concluded, he can say to the owner 'Harei she'Lecha Lefanecha!'?, but not afterwards.

Explanation #1 (concl.): And the current S'vara (which differentiates between before Nigmar Dino and afterwards) goes according to the Rabanan, and the Tana states that by Chametz on Pesach they concede to Rebbi Ya'akov).

Question: Rashi's explanation is diffivult, inasmuch as the Gemara there cites the current Sugya, and it is evident there that Rabah, who refutes Rav Chisda's suggestion and concludes that, since they do not argue by Chametz on Pesach 'Everybody agrees that by Isurei Hana'ah, we say 'Harei she'Lecha Lefanecha!', was not aware of the Beraisa ...

Question (cont.): ... and it is Rabah bar Shmuel who cited it, and Rav Chisda said to him that if he finds them, he should not mention it to them.

Explanation #2: The Ri therefore explains that Rabah extrapolates (not from the Beraisa, but) from the fact that they do not argue by Chametz on Pesach (which would have been preferable) because then one could not have erred and explained their Machlokes in a different way.

Explanation #1: Rashi explains that he actually handed it over to Beis-Din to declare it Chayav Sekilah, which explains why he cannot subsequently say (to the owner) 'Harei she'Lecha Lefnecha'.

Inference: According to that, we can establish the entire section of the Mishnah in ha'Gozel Kama (Bava Kama, later on Daf 96b) like the Rabanan of Rebbi Ya'akov, based on the refutation of Rabah.

Inference (cont.): Whereas when, in connection with the ox that is going out to be stoned, the Mishnah there permits him to say 'Harei she'Lecha Lefnecha' it is speaking where Beis-Din seized the ox on their own initiative.

Alternative: However Rashi there explains that it is only the Reisha that the Gemara establishes like the Rabanan, but the Seifa 'Shor ha'Yotzei Lisakel' does not go like the Rabanan but like Rebbi Ya'akov exclusively.

Reason: And he does this in order to establish 'Shor ha'Yotzei Lisakel' of our Mishnah where Beis-Din seized the ox on their own initiative, similar to the Beraisa.

Question #1: If this is not considered a Hezek Nikar (a discernable damage), then even if he handed it over to the Beis-Din, he ought not to be Chayav; whereas if it is, why is he Patur, even where Beis-Din seize it on their own initiative - since he was obligated to guard it against falling into the hands of Beis-Din.

Question #2: Moreover, if he is Patur there where they seize it on their own initiative, he ought also to be Patur if he hands it over to them, seeing as, when all's said and done, they will eventually seize it anyway, in which case he does not cause the owner any loss, even when he hands it over to them?

Explanation #2: The Ri therefore explains that even if Beis-Din seize the ox on their own initiative, the Shomer is Chayav ...

Reason: Because the fact that the animal fell into the hands of Beis-Din is considered a Hezek Nikar, and since this happened due to his negligence, he is Chayav, and he cannot claim 'Harei she'Lecha Lefanecha!' ...

Reason cont.): ... in the way that one can in the case of Chametz ve'Avar alav ha'Pesach' (later 96b), which is a Hezek she'Eino Nikar (for which reason one can claim 'Harei she'Lecha Lefanecha!').

Explanation #2 (cont.): Whereas Rebbi Ya'akov does not consider the fact that it fell into the hands of Beis-Din a Hezek Nikar until they have issued a ruling that it is Chayav Misah ...

Reason: Seeing as they would have issued the ruling even if it had not fallen into their hands.

Reason (cont.): It therefore transpires that the owner loses nothing by the fact that the ox fell into the hands of Beis-Din, as it is as if they concluded its Din in its absence, because even then it would have been forbidden, in which case it is a Hezek she'Eino Nikar.

Reason (concl.): ... which is why he can say to the owner 'Harei she'Lecha Lefanecha' like by 'Chametz ve'Avar alav ha'Pesach'.

Refuted Explanation: And 've'I Ahadreseih ... ' is not a reason - to explain why he should be Chayav, since the Chiyuv is not dependent upon that, as Rashi explains.

Correct Explanation: But it comes to explain the owner's claim that Beis-Din could not have then concluded the Din in its absence, and now the Shomer was responsible for the ox falling into the hands of Beis-Din, thereby enabling them to conclude the Din of the ox

Correct Explanation (cont.): And since the owner loses as a result of the animal falling into their hands, it is considered a Hezek Nikar, preventing him from claiming 'Harei she'Lecha Lefanecha!'

Support: And the Gemara in 'ha'Nizakin' Gitin, Daf 53b) too, implies that by Hezek Nikar one cannot claim 'Harei she'Lecha Lefanecha!' ...

Support (cont.): ...since it asks from the Mishnah of 'Gazal Matbe'a ve'Nifsal [which became disqualified])' ... "And if we would say 'Hezek she'Eino Nikar Sh'meih Hezek" (because it is considered as if it is discernable) ...

Support (concl.): ... on what grounds can he say to him 'Harei she'Lecha Lefanecha', seeing as it is theft and he must pay him in full?', bearing in mind that this is not the money that he stole, since the damage is considered as if it is discernable, as there is no bigger change than that had it been discernable?

In Conclusion: Consequently, in a case of a Shor Tam that damages whilst under the jurisdiction of a Shomer even before the Din has been concluded, the Shomer will not be Patur if he returns it ...

Reason: ... seeing as it damaged due to his negligence and it fell into the hands of the Nizak conclusively, according to Rebbi Akiva ...

Reason (cont.): ... and to be Meshubad to him, according to Rebbi Yishmael, to claim from its body. Either way, this turns it into a Hezek Nikar - since the owner loses due to the fact that it has fallen into the hands of others.

In Conclusion (concl.): And he cannot claim 'Harei she'Lecha Lefanecha!', as he could do in the case where the Shor killed someone, even after the G'mar Din, according to Rebbi Ya'akov, and according to the Rabanan, at least before the G'mar Din, and in the case of Chametz unanimously.

Implied Question: Even though we Darshen 'ke'Misas ha'Ba'alim kach Misas ha'Shor' ...

Answer: ... concerning this issue it is not logical to Darshen it.

Additional Statement: In the same manner it could have said that they are all Patur if they guarded it properly except for a Sho'el, who is Chayav for Onsin.

Implied Question: And even the Sho'el, granted he is obligated to pay the value of the ox to the owner ...

Answer: ... he does not have to pay Kofer.

Explanation #1: The explanation (of 'Chezkas Shimur') is not the same as the 'Chezkas Shimur' in the first Perek (on Daf 15a) in connection with the Machlokes of 'Palga Nizka Kenasa' ...

Explanation #1 (cont.): ... where it means that it (the animal) does not require guarding, since it is not its way to damage like Shein and Regel (do) ...

Explanation #1 (concl.): ... whereas 'Chezkas Shimur here means that people tend to guard it, only S'tam their guarding is inferior.

Alternative Text: Rabeinu Tam has the text 'be'Chezkas Shimur' in Rebbi Meir, and 'La'av be'Chezkas Shimur' in Rebbi Yehudah.

Explanation #2: According to that text the Gemara is saying - 'What is Rebbi Meir's reason? He holds "S'tam Shevarim are considered be'Chezkas Shimur by the owner, who thinks that they do not tend to damage and who does not therefore bother to guard them'.

Explanation #2 (cont.): ... whereas according to Rebbi Yehudah, owners do not consider S'tam Sh'varim be'Chezkas Shimur, and consequently, they guard them with an inferior guarding.

Explanation #2 (cont.): And according to this text, 'Chezkas Shimur' here has the same meaning as Chezkas Shimur in the first Perek.

Conclusion: Both Rebbi Meir and Rebbi Yehudah however, hold 'Palga Nizka K'nasa'.

Alternative Text: Tosfos agrees with the text that reads 've'Ha Miba'i leih le'Gufeih?'

Reason: He (Rav Ada bar Ahavah) says this from a S'vara - because is the fact that it a Mu'ad a reason that it should be worse, to make him Patur even from Chatzi Nezek with an inferior guarding?

Question: It is in order to apply 'Tzad Tamus' le'Chumra from a S'vara, as Tosfos explained ...

Question (cont.): ... but from where do we learn to apply it even le'Kula, to pay only mi'Gufo, and not to appoint a guardian?

Answer: Since we are obligated to say 'Tzad Tamus bi'Mekomah Omedes' le'Chumra, we will apply it also le'Kula.

Conclusion: We cannot however apply it with regard to exempting him from paying when he admits liability according to the opinion that 'Palga de'Nizka K'nasa' ...

Reason: ... because, since it has become a Mu'ad, it is no longer a K'nas.

Explanation #1: We could say that this statement is Davka, because the right Keren is more apt to damage than the left one ...

Explanation #1 (cont.): ... in which case if it is Mu'ad for the left Keren, then how much more so for the right one.

Explanation #2: Or perhaps it is not, and the Tana merely mentions the more common case.