Observation: Truthfully, one can differentiate that it is not possible there to say that a person knows (that a sale of a field during Yovel is invalid) just as he knows that one cannot really be Mekadesh his sister, as Rav indeed holds the sale (during Yovel) is valid.

Implied Question: The Beraisa states in Kesuvos (52a) that if she (his wife) was captured and they were asking until ten times her real worth, the first time she is redeemed. (Note: How, then, can our Gemara suggest that Levi bar Darga perhaps did not do the right thing?)

Answer: A person's wife is different, as she is like he himself more than his daughter who is discussed here. Chazal did make any limitations regarding a person redeeming himself that he cannot give everything he has for his freedom.

Implied Question: Rebbi Yehoshua ben Chananya redeemed a child for a large amount of money, as stated later (58a). (Note: How could he do so if our Gemara frowns on this practice?)

Answer#1: The child was extremely learned (and therefore was an exception to the rule).

Answer#2: Alternatively, during the destruction of the Beis Hamikdash, it was not possible to make this decree in order that they should not capture more slaves (as they were already exiled and many were enslaved).

Explanation#1: Rashi explains that this is because it is a "Sfeik Sfeika" -- "doubt of a doubt." We are unsure whether or not a Jew wrote it. Even if a Nochri wrote it, perhaps he wrote it in order to sell it to a Jew and not with intent for Avodah Zarah.

Question: This does not appear correct. Rav Nachman says that if a Nochri wrote it, it should be placed in Genizah. This implies that it should be placed in Genizah even if it was written in order to sell it to a Jew. This is as the Gemara later explains, that whoever is not included in "tying" (the Mitzvah of Tefilin) is not included in "writing" (i.e. a valid Sefer Torah).

Explanation#2: Rather, the reason that some say we could use it to read is because it is far more likely that a Jew wrote the Sefer Torah, as Nochrim do not usually write Sifrei Torah.

Implied Question: It is possible to say that the Tana is Rabban Shimon ben Gamliel, as he requires that it be written Lishmah, as he says later. (Note: Why didn't our Gemara choose to say that the author is Rabban Shimon ben Gamliel?)

Answer: However, the Gemara preferred to quote a Tana who explicitly says this particular law.

Opinion#1: Rabeinu Tam extrapolated from our Gemara that a woman cannot tie a Lulav or Tzitzis, as she is not commanded in the Mitzvah.

Question: This does not seem correct. In Menachos (42a), we derive that Tzitzis cannot be made from a Nochri from the Pasuk, "Bnei Yisrael...v'Asu" -- "Bnei Yisrael...and they shall make." This implies that Nochrim cannot make Tzitzis. However, (the fact that the Gemara did not exclude women) this implies that woman can make Tzitzis. We similarly say that a Sukah made by Nochrim, women, for animals, or Kusim is kosher, as stated in the Gemara in Sukah (8b). (Note: We see that something can be made to be used to fulfill a Mitzvah even by those who are not commanded in that particular Mitzvah.)

Opinion#2: Only regarding a Sefer Torah, Tefilin, and Mezuzos where the Pasuk says, "u'Keshartem...u'Chisavtem" -- "and you will tie...and you will write" do we derive that anyone who is not included in tying is not included in writing.

Opinion: We rule like Rabban Shimon ben Gamliel who requires that the processing of the parchment must be Lishmah. This is as is apparent from the Gemara later (54b). A person came before Rebbi Avahu and said to him, "I did not process the parchment, that I used to write my Sefer Torah, Lishmah." He (Rebbi Avahu) concluded that this scribe is believed to lose his pay, but he is not believed to make the Sefer Torah (that had already been transferred to the possession of the buyer) invalid.

Abaye and Rava argue in Sanhedrin (48b) regarding whether or not preparing something for a certain use gives the item the status of that object. The Gemara there says that their argument is the same as the argument between Rabban Shimon ben Gamliel and the Rabbanan.

This is unlike Rashi's explanation of the Gemara there that Abaye holds preparation establishes the status, like Rabban Shimon ben Gamliel who holds that the processing is required to be Lishmah

If so, the halachic rulings in these Gemaros would contradict each other, as we always rule like Rava and unlike Abaye, besides for the six cases of YA'L KgaM (each of the caps stands for a case in the Gemara where we rule like Abaye).

Rather, Rabeinu Tam explains that Abaye holds like the Rabbanan that do not require processing Lishmah. Other types of preparation can be done, such as preparing them and doing Sirtut (etching the lines on the top and bottom of each row). Being that preparation is significant, this type of preparation is sufficient. Rava holds like Rabban Shimon ben Gamliel that the processing of the leather itself has to be done Lishmah, and not merely a small amount of preparation.

Implied Question: We say in Menachos (42b) that Rav holds like the Rabbanan, and Shmuel holds like Rabban Shimon ben Gamliel. The law generally follows Rav in matters of prohibitions (and Shmuel in monetary matters). (Note: Doesn't this contradict our ruling that the law is like Rabban Shimon ben Gamliel?)

Answer: The law in this case follows the opinion of Shmuel.

Implied Question: Abaye asked Rav Shmuel bar Yehudah, how can one dye this Techeiles? Rav Shmuel answered that one brings the blood of the Chilazon and dye, puts them in a pot (and boils it), takes a little in an egg and puts a bit of it on some stuffing (i.e. wool). We then throw away the egg and burn that wool in a fire. This implies that the dying of the wool must be done Lishmah (as this is why we throw away the part that was dyed as a test, as it was not done Lishmah, but only for a test). (Note: This implies that Abaye agrees that preparation must be done Lishmah, further implying that he is the one who holds like Rabban Shimon ben Gamliel, not Rava.)

Answer: Abaye did not accept this answer from Rav Shmuel, as he does not require processing, sewing, and dying Lishmah.

Opinion: Rashi implies that this is also referring to Sefarim.

Question: This is slightly difficult. How can the Shas equate Sefarim, whose value is great and we would only say that one can pay a Trefik (half a dinar) more, to Tefilin and Mezuzos?

Answer: Therefore, it seems that it is only discussing Tefilin and Mezuzos.

Question: This is difficult. Perhaps they do not require Kesivah Lishmah, as they are generally written Lishmah. However, general processing of skins are not for Tefilin.

It is not logical to assume the question is from processing to processing. Being that the Gemara says that writing Lishmah is not necessary, it implies that the question is from writing.