Gittin, Chapter 2, Mishnah 4. The Mishnah opens: "Ein kosvin bimchubar lakarka" - a get may not be written while it is attached to the ground. The reason is derived from the verse mentioned in the previous Mishnah, "venasan beyadah" ("and he shall place it in her hand"), from which we learn that the get must be fit to be placed in her hand; and as long as it is attached to the ground, it cannot be given to her.
The Tofes and the Toref:
The Gemara explains that the Mishnah is teaching us that, ideally, one may not write even the standard portion of the get while it is attached, and this is because of a rabbinic decree. There are two parts to a get:
The tofes - the fixed portion, consisting of the wording that appears identically in every get.
The toref - the essential portion, in which all the particulars are written: the names of the husband and the wife, the date, and the like.
The concern is that the toref might also come to be written while attached, and therefore the Sages forbade even the tofes at the outset.
The Mishnah continues: "Kasvo bimchubar, telasho vechasmo unesano lah - kasher" - if he wrote it while attached, then detached it, signed it and gave it to her, it is valid. In other words, after the fact, if the general portion was written while it was still attached to the ground, and afterward it was detached from the ground and only then was the toref written, the get signed and given to her, the get is valid.
Two ways of explaining the Mishnah:
According to Rabbi Elazar - who holds "edei mesirah kartei," that the primary witnesses are those who observe the handing over of the get. In his view, when the Torah says "vechasav lah" ("and he shall write for her"), it refers to the writing of the get itself and not to the signing of the witnesses. According to this explanation, the word "vechasmo" in the Mishnah means that after the detaching, the get was written.
According to Rabbi Meir - who holds "edei chasimah kartei," that the primary witnesses are those who sign the get, and that when the Torah says "vechasav" it actually refers to the signatures. According to this explanation, ideally one may not write the toref while attached - the particulars of the get, the names of the husband and the wife, the date and so on - nor may one sign it there; but after the fact, if the particulars were written and afterward the get was detached and signed, with the word "vechasmo" understood literally, referring to the actual signatures, the get is valid.
It emerges that according to Rabbi Meir's explanation, the main body of the get was written while it was still attached, and only the signatures were done after it was detached - and even so, after the fact the get is valid.
The view of Rabbi Yehudah:
The Mishnah continues: "Rabbi Yehudah posel, ad shetehei kesivasah vachasimasah betalush" - Rabbi Yehudah invalidates it unless both its writing and its signing are done on something detached. Rabbi Yehudah holds that both the writing and the signatures must be done while the get is detached from the ground, and even the tofes - the portion whose wording is fixed - is included in the prohibition, as a decree on account of the other parts of the get.
The view of Rabbi Yehudah ben Beseira:
Rabbi Yehudah ben Beseira adds that a get may not be written on two types of material:
Erased paper - paper from which writing has already been erased. Once it has been erased, it is no longer recognizable whether what is before us is the original text, and perhaps someone erased above the signatures and wrote something else.
Difteira - parchment that was not properly processed.
And the reason is: "Mipnei shehu yachol lehizdayef" - because it can be forged.
"Vachachamim machshirin" - and the Sages validate it: the Sages hold that even these materials may be used and the get is valid. The reason is that the Sages follow the view of Rabbi Elazar that "edei mesirah kartei," that the witnesses who testify about the handing over of the get are the primary witnesses, and therefore we rely on them regarding the facts and the particulars.
In summary: in this Mishnah we learned that a get may not be written while attached to the ground, based on the law of "venasan beyadah," and that the prohibition at the outset applies even to the tofes, because of the decree lest the toref be written that way. We examined two ways of explaining the Mishnah - according to Rabbi Elazar, who holds "edei mesirah kartei," and according to Rabbi Meir, who holds "edei chasimah kartei" - as well as the view of Rabbi Yehudah, who invalidates the get unless its writing and its signing are done on something detached. We also learned the view of Rabbi Yehudah ben Beseira, who invalidates erased paper and difteira because they can be forged, and the view of the Sages, who validate them, following the position of "edei mesirah kartei."