Gemara

84b (Mishnah): If he wrote it (the Tenai) in the Get, even if it was later erased, the Get is Pasul.

Opinion #1 (Rav Safra): The case is, he wrote the Tenai in the Get.

One might have thought that the Mishnah discusses only a Tenai written after the Toref (this will be defined), but a Tenai before the Toref disqualifies even if the Tenai was not written in the Get. Rav Safra teaches that this is not so.

Opinion #2 (Rava): The Mishnah discusses a Tenai after the Toref. If the Tenai precedes the Toref, even if it was not written in the Get, the Get is Pasul.

For this reason, Rava would silence the husband until the Toref was written.

(Beraisa - Rebbi): Any Tenai disqualifies a Get;

Chachamim say, only a Tenai that disqualifies a Get orally, disqualifies it when it is written in it: 'Chutz (except for Ploni)', disqualifies orally, or if it is written. 'Al Menas that you don't marry Ploni' does not disqualify orally, nor if it is written.

Opinion #1 (R. Zeira): Rebbi and Chachamim argue about a Tenai before the Toref. Rebbi decrees to disqualify 'Al Menas' due to 'Chutz'. Chachamim do not decree. All agree that Tena'im after the Toref do not disqualify. The Mishnah disqualifies only written Tena'im. We said that it discusses when he said ''Chutz';

If the Mishnah discusses before the Toref, it is like Chachamim. If it discusses after the Toref, all agree to it.

Opinion #2 (Rava): Rebbi and Chachamim argue about a Tenai after the Toref. Rebbi decrees to disqualify it due to a Tenai before the Toref. Chachamim do not decree. All agree that Tena'im before the Toref disqualify a Get. The Mishnah disqualifies only written Tena'im. We said that it discusses when he said ''Chutz'. The Mishnah discusses after the Toref. It is like Chachamim.

(R. Avin's father - Beraisa): All agree that a Get written on Tenai is Pasul.

(R. Zeira): They argue in this case! Rather, the correct text of the Beraisa must say that all agree that it is valid, when the Tenai was after the Toref.

Rishonim

Rif and Rosh (9:3): The Halachah follows Rava; the Mishnah discusses a Tenai after the Toref. A Tenai before the Toref disqualifies even if it was not written in the Get. Rebbi and Chachamim argue about a Tenai after the Toref. Rebbi decrees to disqualify it due to a Tenai before the Toref. Chachamim do not decree. Our Mishnah disqualifies only written Tena'im, and only 'Chutz', but not 'Al Menas.' It discusses Tana'im after the Toref. It is like Chachamim.

Rambam (Hilchos Gerushin 8:3): To divorce conditionally, one does not say 'write' or 'write and give a Get Al Tenai', and surely he does not write the Tenai in the Get! Rather, he tells the scribe and witnesses to write and sign without any Tenai. Afterwards, he or his Shali'ach gives the Get to her and says 'you are divorced Al Menas so and so.'

Rambam (4): If the Tenai was written in the Get after the Toref was written, it is Kosher, whether the witnesses signed before or after the Tenai was written. If the Tenai was written before the Toref, even if he wrote 'Al Menas so and so', it is Safek divorce, for he still has privileges (potential to nullify the divorce) in the Get. Similarly, if he stipulated verbally before the Toref was written, it is Safek divorce.

Magid Mishneh: Rava is most stringent, and he allows Al Menas after the Toref according to Chachamim. Surely, the Halachah follows Chachamim.

Poskim

Shulchan Aruch (EH 147:2): If one wrote a Tenai in the Get after the Toref was written, the Get is Kosher, whether the witnesses signed before or after the Tenai was written. If the Tenai was written before the Toref, even if he wrote 'Al Menas so and so', it is Safek divorce, for he still has privileges in the Get. Similarly, if he stipulated verbally before the Toref was written, it is Safek divorce.

Beis Shmuel (3): Tosfos (85a DH Aval) disqualifies mid'Oraisa a verbal Tenai of Chutz before the Toref. The Ran asked, if so we should decree to forbid Chutz after the Toref! Tosfos can hold that we do not decree after the Toref due to before the Toref. If Chutz was written after the Toref, it is Pasul because it is as if the Get was given Chutz l'Ploni.

Beis Yosef (DH ha'Matil): When one commanded to write a Get on Tenai, one may not divorce with it even if he later pardoned the Tenai, since it could not divorce at the time it was written.

Beis Yosef (DH u'Mah she'Chosav Rabeinu): The Tur says that 'before the Toref' is before writing 'you are permitted to all men', like the Rosh (Teshuvah 46:1). The Rashba (1245) learns from 20a that this is not the Toref. A man gave a Sefer Torah to his wife for her Get. The Gemara asked that their names are not in it. It did not ask that we need 'you are permitted to all men'! Perhaps the Gemara could have asked that as well. We do not find 'you are permitted to all men' in early Tofsei Gitin. Even if you will say that it is needed, it is part of the Toref.

Note: Our text of the Rashba learns from a Mishnah (26a), which requires one who writes the Tofes to leave over only the names and the date. Even though Shmuel requires leaving over also 'you are permitted...', this does not mean that it is part of the Toref. It seems that the Rashba should conclude 'even if you will say that it is needed, it is not part of the Toref (Hagahah 314 in Chidushei ha'Rashba (85b), Mosad ha'Rav Kuk edition).

Beis Yosef (DH ul'Inyan Get): A case occurred in which a Get was written on Tenai. The Mizrachi disqualified it, even though the husband went abroad. He did not want to rely on the lenient opinions, even though they are the majority. He was too extreme. B'Di'eved, we may rely on those who permit, since they are the majority, especially in pressed circumstances. Most Meforshim say that the entire Pesul is mid'Rabanan!

Beis Yosef (DH ul'Inyan Mah): The Rambam says that if there was a verbal Tenai before the Toref, she is Safek divorced. The Magid Mishneh says that he learns from the Yerushalmi, which disqualifies due to Breirah (perhaps it was not written l'Shem Kerisus). We do not find that the Bavli argues. However, the Ran (44b DH Gemara) says that the Bavli disqualifies due to a decree, not due to Breirah.

Gra (3): The Rambam holds the Bavli explains that Rebbi disqualifies due to a decree, but Chachamim disqualify due to Breirah. However, Tana'im that are Mevatel a Get, or are after the Toref, disqualify due to a decree.

Question (Beis Shmuel 3): The Rambam says that it is Safek divorce due to Ein Breirah. This refutes the Yam Shel Shlomo (Bava Kama 7:9, who says that the Rambam holds Ein Breirah for mid'Oraisa laws, even to be lenient).