Gittin 26B

קשיא דרבי אלעזר אדרבי אלעזר! תרי תנאי ואליבא דרבי אלעזר.

The Talmud asks: If the first clause of the Mishnah is in accordance with the opinion of R' Elazar, this is difficult, as there is a contradiction between the explicit statement of R' Elazar in the last clause of the Mishnah, where he rules that a scribe may not write the standard part of a bill of divorce in advance, and the statement of R' Elazar in the first clause of the Mishnah that a scribe may write the standard part of a bill of divorce in advance. The Talmud answers: There are two tanna’im, and they disagree with regard to the opinion of R' Elazar.

רבי שבתי אמר חזקיה: משום קטטה; ורבי מאיר היא, דאמר: עדי חתימה כרתי,

The Talmud returns to discussing the ordinance mentioned in the Mishnah. R' Shabbetai says that Ḥizkiyya says: The ordinance mentioned in the Mishnah was not instituted for the benefit of scribes, allowing them to prepare the standard part of bills of divorce in advance. The ordinance was instituted due to the desire to prevent a quarrel, and it is in accordance with the opinion of R' Meir, who says: Signatory witnesses on the bill of divorce effect the divorce, and there is no need for the bill of divorce to be written for the sake of the woman.

ובדין הוא דאפילו תורף נמי לכתוב; וזמנין דשמעה ליה לסופר דקא כתיב, וסברה איהו קאמר ליה, והוה לה קטטה בהדיה.

He continues to explain the ordinance: And by right it should have been that the scribe would be permitted to write even the essential part of the bill of divorce as well. But sometimes there might be a wife who hears the scribe who by chance is writing in advance a bill of divorce with her name, and she thinks that her husband told him to write the bill of divorce on his behalf, and she will have a quarrel with him. Therefore, the rabbis instituted an ordinance that the scribe may not write the essential part of the bill of divorce in advance, as it includes the names of the husband and the wife.