1) A GET WITHOUT A DATE IS VALID B'DI'EVED
QUESTION: The Mishnah states that there are three types of Gitin which are deemed invalid, but if a woman who was divorced with such a Get remarried and had a child, the child from the second marriage is not a Mamzer (because the Get is valid b'Di'eved). One of these three Gitin is a Get with witnesses signed on it but with no date.
How can a Get with no date be valid even b'Di'eved? The date is an essential part of the Get! Moreover, such a Get violates the "Matbe'a" (standard text) which the Chachamim established for Gitin. The Gemara (80a) states that the Chachamim instituted that one must write the year of the local, reigning king in the Get because of Shalom Malchus (the requirement to maintain peaceful relations with the authorities). The Gemara there mentions that one who alters the text of a Get as established by the Chachamim causes the children from the subsequent marriage to be Mamzerim. How, then, can a Get without a date be valid b'Di'eved to prevent the children from being Mamzerim?
(a) The RASHBA answers that the requirement to write the date in a Get is only l'Chatchilah. The Gemara itself (17b) states that failure to fulfill this requirement prevents a woman with this type of Get from remarrying. This implies, however, that it does not have the power to make a child from a subsequent marriage a Mamzer.
The Rashba explains that the reason why the Chachamim instituted that the name of the reigning king be written in the Get is for the sake of Shalom Malchus. A transgression of this requirement would be the writing of the name of a different king, for this would offend the local king and harm the Jews' relationship with him. If, however, one mentions no king or year at all in the Get, the king presumably will not care. Therefore, this is not a reason to invalidate the Get entirely.
(b) RABEINU KRESKAS writes the same answer as the Rashba for why omitting the year of the king does not invalidate the Get. However, he asserts that since the Get is not valid l'Chatchilah, omitting the year of the king should be considered an alteration of the "Matbe'a" of the Chachamim and the child should be a Mamzer.
Rabeinu Kreskas gives a different answer to this question based on the Gemara earlier (17b). The Gemara states that when one writes as the date of the Get the current Shemitah cycle but does not write the actual year, the Get is valid. Similarly, if one writes only the year but not the month, or the month but not the week, or the week but not the day on which the Get is written, the Get is valid. This clearly shows that the requirement to write the date in a Get is not absolute. Writing the number of the Shemitah cycle does not provide an accurate date, and yet the Get is valid. Accordingly, even if no date is written the Get is valid b'Di'eved, and this is not considered a change in the "Matbe'a" established by the Chachamim for Gitin.
(c) The PNEI YEHOSHUA (79b) notes that RASHI there would not agree entirely with the answer of the Rashba. The Mishnah there states that a Get which contains only the number of years the Beis ha'Mikdash has been standing, or the number of years it has been destroyed, is invalid. Rashi (DH O she'Kasvah) explains that the Get is invalid because it was not written based on the year of the king. The Pnei Yehoshua writes that in such a case, the reigning king will not be jealous of the fact that the destruction of the Beis ha'Mikdash is mentioned in the Get, since such a date does not challenge his authority in any way and is merely an expression of the Jews' sorrow that the Beis ha'Mikdash is no longer standing. The fact that Rashi says that the Get is invalid because the year of the king is not mentioned implies that Rashi maintains that the decree to mention the name of the king in a Get was in order to actively honor the king and not merely to refrain from insulting him by mentioning another king (as the Rashba explains).
This is also implied by Rashi later (80a, DH Mishum). Rashi explains that the reason for writing the name of the king in a Get is that the royalty should feel distinguished in the eyes of the Jews who mention the kings' names in their documents. However, the Pnei Yehoshua suggests that even Rashi will agree that if no date is written at all in the Get, the Get is valid. When the year for the destruction of the Beis ha'Mikdash is written, although it is not considered an insult to the king, it is a lack of honor since a different dating system was mentioned. In contrast, when no date at all is written, Rashi will agree that there is no display of disrespect to the king. (D. BLOOM)
2) THE GET MUST BE SIGNED "LISHMAH" OR GIVEN TO THE WOMAN "LISHMAH"
QUESTION: The Mishnah states that if two men sent two Gitin with identical names of husbands and wives and they become mixed up, both Gitin should be given to both women. The Gemara quotes Rebbi Yirmeyah who says that the Mishnah cannot follow the view of Rebbi Elazar who rules that "Edei Mesirah Kartei" (the witnesses who observe the handing over of the Get effect the divorce). Since it is not known which Get was written for which woman, the Edei Mesirah do not know which Get effects each divorce.
This Gemara seems to contradict a principle stated by the RIF (47b of the pages of the Rif). The Rif asserts that even Rebbi Elazar, who rules that "Edei Mesirah Kartei," agrees that "Edei Chasimah Kartei." This means that Rebbi Elazar understands that when there are no witnesses who see the giving of the Get, the witnesses signed on the Get effect the divorce.
(RABEINU KRESKAS (DH u'Shmuel) proves the Rif's principle from the fact that Shmuel rules that if the scribe wrote a Get and one witness signed, the Get is valid. Shmuel must be referring to a case in which there are no Edei Mesirah, because if there would be Edei Mesirah it would be irrelevant whether or not the scribe and the witness signed. It is logical that Shmuel rules like Rebbi Elazar that "Edei Mesirah Kartei," as the Gemara here rules like Rebbi Elazar. Accordingly, even when there are no Edei Mesirah, Rebbi Elazar agrees that the Get is valid because of the Edei Chasimah.)
According to the Rif, why does Rebbi Yirmeyah say that the Mishnah cannot follow Rebbi Elazar? Rebbi Elazar agrees that when there are no witnesses who see the giving of the Get, the Get is valid because witnesses signed the Get!
(a) RABEINU KRESKAS answers in the name of the RAMBAN that Rebbi Yirmeyah understands, at this stage of the Gemara, that just as Rebbi Meir maintains that the witnesses must sign the Get Lishmah because they (the Edei Chasimah) effect the divorce, Rebbi Elazar maintains that the witnesses must witness the giving of the Get Lishmah.
The Ramban explains that when the Torah states, "He shall write for her (Lah) a Sefer Kerisus and give it into her hand," the word "Lah" -- from which the requirement of Lishmah is derived -- refers not only to "he shall write" but also to "and give." According to Rebbi Elazar, the "Kerisus" of the Get is accomplished not only from its writing but also from its delivery. Since Edei Mesirah alone are capable of effecting the divorce according to Rebbi Elazar, it follows that the Get must always be given Lishmah. Therefore, since Rebbi Elazar requires Nesinah Lishmah, Rebbi Yirmeyah maintains that the Mishnah cannot be consistent with the view of Rebbi Elazar, because when the two Gitin are given to the two women the witnesses do not know which Get is given for which woman.
(b) RABEINU KRESKAS suggests a different reason for why one Nesinah Lishmah is necessary according to Rebbi Elazar. Rebbi Elazar requires that the Get be given Lishmah according to Torah law when one divorces his wife based on the testimony of Edei Mesirah. It follows that when the divorce is accomplished by the Edei Chasimah who sign the Get Lishmah, the Chachamim instituted that the Nesinah should also be Lishmah, lest people rely on the giving of a Get that is not Lishmah even when no Edei Chasimah sign the Get. This is similar to the reasoning of the Gemara earlier (4a) that Rebbi Elazar agrees that if a Get is Mezuyaf mi'Tocho, it is invalid. This means that when there are no witnesses at all signed on the Get it still can be valid, provided that it was handed over in front of witnesses, Edei Mesirah. However, when the witnesses signed on the Get are invalid or did not sign Lishmah, the Get is invalid; it is worse than a Get with no signatures at all. This is because people may rely on such a Get even when there are no Edei Mesirah. Similarly, the Get in the case of the Mishnah here is invalid even when there are Edei Chasimah, lest people rely on the giving of a Get that is not done Lishmah when there are no Edei Chasimah. (D. BLOOM)