Gemara

Question: (In a Get Mekushar, witnesses sign on the other side, opposite the text.) Perhaps the bearer will add under the text!

Answer: The text says 'Sharir v'Kayam' (at the end).

Question: Perhaps he will add, and write another 'Sharir v'Kayam'!

Answer: A document may say 'Sharir v'Kayam' only once.

Question: Perhaps he will erase the first 'Sharir v'Kayam', add to the text, and write 'Sharir v'Kayam'!

Answer: R. Yochanan taught that if words were Teluyos (written between the lines), and they are Mekuyam (the document mentions them) at the end, it is valid. An erasure invalidates a Get, even if the document mentions it at the end, i.e. if it is in a place fitting and large enough for it to say 'Sharir v'Kayam.'

161b (R. Yitzchak bar Yosef): An erasure (even if it does not invalidate a Get, due to its place or its small size) must be Mekuyam in the Get.

Rishonim

The Rif brings our Gemara.

Nimukei Yosef (DH Omar ha'Mechaber): The Ramban says that the enactment to write Sharir v'Kayam and to write it only once, was in a Get Mekushar. It was enacted due to concern for forgery, lest one add or detract from it. There was no enactment for a regular document. If it does not say Sharir v'Kayam, or says it twice, it is Kosher. Our custom is is to write it two or three times. Also, if an erasure is in a place fitting and large enough for it to say 'Sharir v'Kayam', if it is Mekuyam, if it is a regular document, it is Kosher. The Ritva says so; our custom is is to disqualify it. The Gemara says that we do not learn from the last line, but our custom is to learn from it! The Ramban toiled to explain this. The Gemara says that one must recap the document in the last line. The RI ha'Zaken and the Ritva say that this is a good counsel, but if one did not do so, the document is Kosher.

Rambam (Hilchos Malveh 27:8): One must be Mekayem every erasure at the end of the document, and say 'this letter or word or line is written over an erasure or between the lines, and it is all valid.' If an erasure is in a place for and large enough for it to say 'Sharir v'Kayam', even if it is Mekuyam, it is Pasul. Perhaps he erased it, added text, and was Mekayem it with space between the text and the witnesses.

Magid Mishneh: The Rambam connotes that a document does not need Sharir v'Kayam. It is only if there are erasures and Teluyos, to enable learning from them. Also, he holds that one should not write the Kiyum of erasures and Teluyos in the last line, for we do not learn from it. This is clear for the Gemara. Our custom is to write Kiyumim in the last line. Meforshim toiled to justify this. They say that every document must say Sharir v'Kayam, and that we do not learn from the last line only if it is written after Sharir v'Kayam. They made the practice to finish the document in the middle of a line, and the witnesses sign in the rest of the line. Surely, they would not sign there unless the document ended earlier in the line!

Rosh (10:2): R. Tam says that one should make a Kiyum of erasures and Teluyos before 'we acquired from him' before the last line. Nowadays, the custom is to be Mekuyam erasures and Teluyos after 'we acquired', in the last line, for the custom is to write Sharir v'Kayam in all documents. Therefore, one cannot forge, and we learn from the last line. One need not recap the document in the last line. However, this is difficult. Since a document is Kosher without Sharir v'Kayam, like it is clear from our Gemara, we should be concerned lest a document was written without it, and the bearer erased unfavorable clauses, and wrote what he wants on top, and was Mekuyam it in the last line! We can say that since the custom is to write Sharir v'Kayam in all documents, a document without it is Pasul, and witnesses will not sign it until they see it written. Our custom is to write Sharir v'Kayam, and to learn from the last line. Perhaps this is due to were concern lest witnesses distance their signatures two lines from the end of the text (and if there were no Sharir v'Kayam, the bearer could add things afterwards). I disagree. If we were concerned for this, (there is no solution;) perhaps the bearer will cut off the top, write a document in one line, and recap it in the second line (and witnesses are signed underneath)! Rather, the custom is to write Sharir v'Kayam lest there are erasures and Teluyos that must be Mekuyam after the document was finished, and they already wrote 'we acquired from him.' We are Mekuyam the erasures and Teluyos, and then write Sharir v'Kayam. According to this, one may write 'and this should be to you, from me, a Sefer of cutting...' in the last line, even though this might be essential (the Gemara never resolved this). Since we write at the end of a Get 'k'Da'as (like the law of) Moshe v'Yisrael', this is in place of Sharir v'Kayam, so we learn from the last line. However, also in the days of the Tana'im, they used to write 'k'Da'as Moshe v'Yisrael', yet the Gemara says that we do not learn from the last line, both for Gitin of money and of divorce! It seems that they used to write 'k'Da'as Moshe v'Yisrael' in the middle of the Get. Now we write it at the end, so wll. Why do friends of the Chasan sign the Kesuvah and leave two lines between the text and their signatures? Perhaps we do not disqualify the Kesuvah because they sign only for honor, and not for testimony. If witnesses signed in the middle of a line, and what is in front of their signatures was cut off, it is Pasul, for perhaps a Tanai or a clause that harms the bearer was written there. However, if the line above ends with Sharir v'Kayam, it is Kosher if the witnesses signed one under the other. If they signed in one line, it is Pasul, for perhaps it was a document in one line, and the bearer cut the side and wrote this document above.

Poskim

Shulchan Aruch (CM 44:9): Nowadays, the custom is to be Mekuyam erasures and Teluyos after 'we acquired', for the custom is to write Sharir v'Kayam in all documents. Therefore, one cannot forge, and we learn from the last line. One need not recap the document in the last line. Therefore, a document without Sharir v'Kayam is Pasul.

Shach (20): Kiyumim must be before Sharir v'Kayam. Those who do Kiyum afterwards err; this does not help.

Shach (21): Surely, if we see that witnesses signed under the text without any space and it does not say Sharir v'Kayam, the document is Kosher, just we do not learn from the last line. Tosfos and the Rosh could hold that it is Pasul, for in all other documents we learn from the last line. However, the Mechaber (Sa'if 1) says like I said.

Shulchan Aruch (ibid): Witnesses may not sign unless it says Sharir v'Kayam.

Gra (24): There is a Chazakah that witnesses sign only if everything is proper (Sanhedrin 29b).

SMA (14): If there is no Sharir v'Kayam and the witnesses left room, one could add things and conclude Sharir v'Kayam. In such a case, we learn from the last line!

Shulchan Aruch (ibid): If it says Sharir v'Kayam twice, it is Kosher.

Tur: It seems that a document should be Pasul if it says Sharir v'Kayam twice, for perhaps after the first Kiyum, the bearer forged and was Mekayem a second time. However, Ri Bartzeloni says that a regular document is Kosher even if it says Sharir v'Kayam many times.

Beis Yosef (DH ul'Fi): Ri Bartzeloni and the Ramban say that only a Get Mekushar must say Sharir v'Kayam only once. The Rashbatz says that the Rashba agrees. However, if (the latter) Sharir v'Kayam is in the last line it is Pasul, lest (the witnesses left space, and) the bearer added text and another Sharir v'Kayam. If the last line recaps the document, we are not concerned. The Rosh (68:18) connotes that in all documents, the custom is to write it only once.

SMA (15): This is when there is a space between the text and the witnesses. If not, it is Pasul. Perhaps the witnesses left room, and the bearer added and wrote another Sharir v'Kayam!

Shach (23): Ir Shushan says that we are not concerned lest the witnesses left so much room that the bearer added and wrote another Sharir v'Kayam. This is astounding. Throughout the Gemara, Poskim and this Siman we are concerned lest they left a blank line! The SMA says that it is Kosher when there is a space between the text and the witnesses. If so, the Mechaber should have specified!

Taz: The Tur disqualifies it. Presumably, since we see one problem, we are concerned lest the witnesses left two blank lines. Ri Bartzeloni is Machshir, for he permits writing an extra Sharir v'Kayam