1) "B'FANAI NICHTAV CHETZYO"
QUESTION: The Mishnah states that if the Shali'ach who brings the Get from Medinas ha'Yam says "b'Fanai Nichtav Chetzyo" -- "in front of me half of it was written," the Get is invalid.
The Gemara asks that if the primary part of the Get, the part with the names and actual words of the Gerushin, was written in front of the Shali'ach, the Get should be valid and it should not be necessary for the entire Get to be written in front of him. The Gemara answers that the Mishnah refers to a case in which the Shali'ach testified that the second part of the Get, the Tofes, was written in front of him. The writing of the Tofes in his presence is not enough to make the Get valid.
TOSFOS asks that this Gemara's question and answer make sense according to Rabah, who requires that the Shali'ach say "b'Fanai Nichtav" in order to testify that the Get was written Lishmah. Accordingly, it is important that he testify about the part of the Get that makes it valid, and he does not need to testify about the part of the writing of the Get that is not necessary for the Get's validity.
Rava, however, maintains that the Shali'ach must say "b'Fanai Nichtav" in order to be Mekayem the Get. He must say "b'Fanai Nichtav" to differentiate the Kiyum of the Get from the Kiyum of ordinary Shtaros, for which two witnesses are necessary. According to Rava, why must the Shali'ach say "b'Fanai Nichtav" only on the crucial part of the Get? Saying "b'Fanai Nichtav" on any part of the Get is enough to show that this Kiyum is not an ordinary form of Kiyum Shtaros. How does Rava understand the Gemara?
ANSWERS:
(a) TOSFOS answers that if the Shali'ach would say "b'Fanai Nichtav" about the unimportant part of the Get, it would not show that this Kiyum differs from the Kiyum of ordinary Shtaros.
(b) The PNEI YEHOSHUA points out the difficulty inherent in Tosfos' explanation. Any testimony about the writing of the Get, even about an unimportant part, should show that this form of Kiyum is not an ordinary form of Kiyum Shtaros. Moreover, why is it so obvious to the Gemara that saying "b'Fanai Nichtav" about the Toref (the crucial part of the Get) without the Tofes suffices? If it is necessary to show, with a clear Heker, that the Kiyum of this document differs from the Kiyum of ordinary Shtaros, perhaps that Heker must include the entire Shtar. Even if the Get itself is valid, if the Heker is not optimally clear the Shali'ach's testimony may not be accepted as Kiyum for the Get.
The Pnei Yehoshua answers that when the Chachamim instituted the obligation to say "b'Fanai Nichtav" because of the concern that the Kiyum of the Get may be confused with the Kiyum of ordinary Shtaros, the Chachamim did not merely institute that a few words be added to the Shali'ach's testimony. Rather, they instituted an obligation to write the Get in front of the Shali'ach who will deliver it.
Accordingly, the enactment to say "b'Fanai Nichtav" is more than plain words that prevent a potential problem; "b'Fanai Nichtav" must be said because if the Get was not written in front of the Shali'ach, the Get itself is invalid.
According to this understanding, the Gemara is clear. The part of the Get that needs to be written in front of the Shali'ach is the Toref. Since the Tofes, in contrast, is not necessary for the validity of the Get, the Chachamim could not decree that it needs to be written in front of the Shali'ach -- since it does not need to be written at all! The Chachamim could decree that only if the Toref is not written in front of the Shali'ach, the Get is invalid.
(c) The Pnei Yehoshua adds that once the Chachamim decreed that the Shali'ach must say "b'Fanai Nichtav," they included in their enactment the necessity to attest to the validity of the Get -- that is, they it was written Lishmah. Since it is necessary to determine that the Get was written Lishmah, the significant part in this regard is clearly the Toref. (Mordechai Zvi Dicker)

15b----------------------------------------15b

2) WHEN THE SHALI'ACH SAYS THAT HE IS THE SECOND WITNESS WHO SIGNED THE GET
QUESTION: The Gemara discusses a case in which the Shali'ach who delivers the Get states that he saw only one of the two signatories sign the Get. The Get is not valid, even if someone else attests to the authenticity of the second signature.
Rav Chisda explains that even if two witnesses testify about the second signature, the Get still is not valid. Rave argues that if two witnesses testify about the second signature, the Get certainly is valid; two witnesses are not worse than a single Shali'ach's testimony that he saw the second signatory sign the Get. Rather, the Gemara refers to a case in which the Shali'ach joins with another witness and together they testify that they recognize the second signature. In such a case, the Get is not valid.
Rav Ashi argues with Rava and asserts that just as the Shali'ach would be believed if he would say "b'Fanai Nechtam" about the second signature, he would also be believed to testify with another witness about that signature. Accordingly, when the Shali'ach joins with another witness and they testify about the second signature, the Get is valid.
Rav Ashi agrees, however, that if the Shali'ach says about the first signature "b'Fanai Nechtam" and then he declares that he is the second witness who signed the Get, the Get is not valid. His reasoning is that "[the validity of the Get must be established] either entirely with Kiyum ha'Get or entirely with the Takanas Chachamim." That is, either the ordinary form of Kiyum Shtaros must be used for both signatures, or the Takanos Chachamim of "b'Fanai Nichtav uv'Fanai Nechtam" must be used for both signatures. Two different forms of Kiyum may not be used.
Rav Ashi's opinion is difficult to understand. If the Shali'ach would have said "b'Fanai Nechtam" about the second signature, he certainly would have been believed. Why, then, is he not believed when he says that he is the second witness?
ANSWERS:
(a) TOSFOS (DH ANI) answers in the name of the Yerushalmi that since the Shali'ach signed the Get, his testimony of "b'Fanai Nichtav" about the writing of the Get and the other signature is no longer acceptable because he is considered "Noge'a b'Davar." Although he does not stand to gain anything by validating the Get, his involvement in the signing of the Get is enough to activate the principle of, "[the validity of the Get must be established] either entirely with Kiyum ha'Get or entirely with the Takanas Chachamim," and thus the Get is not valid.
The RITVA adds that according to this explanation, even if two witnesses testify about the Shali'ach's signature in the Get, the Shali'ach still is not believed to say "b'Fanai Nechtam" about the other signature. Since he signed the Get, he is slightly biased and his testimony about the other signature is not accepted.
(b) The RAN explains that the Shali'ach's testimony that he is the second witness who signed the Get is not accepted for a different reason. In contrast to the previous case of the Gemara in which the same form of testimony was given about both signatures, in this case there are two different forms of testimony about the two signatures. When the Shali'ach says that the first witness signed the Get in front of him, he is testifying about the signature. When he says, "I am the second witness [who signed the Get]," he is testifying not about his actual signature but about the words written in the Get itself. Since the Shali'ach's testimony of "b'Fanai Nichtav" is believed only because of the Takanas Chachamim, which applies only when he testifies as a single Shali'ach, his testimony cannot combine with his testimony about what is written in the Get. The Takanas Chachamim does not combine with another form of testimony (his own word that he signed the Get), since the two forms of testimony are different. In such a situation, the principle of "[the validity of the Get must be established] either entirely with Kiyum ha'Get or entirely with the Takanas Chachamim" applies. (Mordechai Zvi Dicker)