(Gemara): According to Rebbi, witnesses testify about their own signatures. According to Chachamim, they testify about the content of the document.

Objection: This is obvious!

Answer: One might have thought that Rebbi is unsure whether the witnesses testify about their own signatures or about the content of the document.

If Rebbi was unsure, this would affect the law if one witness died. Rebbi would require two witnesses to testify about his signature.

It would not suffice for the live witness and another person to testify about the signatures.

If so, the live witness would (perhaps) be giving three fourths of the testimony. (Perhaps when he verifies his signature he testifies alone about the content of the document, and he also helps to confirm the other signature.)

Rebbi would be stringent in this case, and also stringent in the case of the Mishnah (when each confirms only his own signature).

Therefore, we needed to teach that Rebbi is sure that they testify about their signatures.

(Rav Yehudah): If one of the witnesses dies, two others are needed to confirm his signature.

In this case Rebbi is more lenient than Chachamim.

Question: What can we do if there is only one other who recognizes his signature (in addition to the live witness)?

Answer (Abaye): The live witness should write his name on a piece of pottery and give it to Beis Din.

Now we do not need him to confirm his own signature, so he may help confirm the other signature.

He should sign specifically on pottery, but not on a parchment, lest a corrupt person find it, and write like he pleases above the signature.

(Mishnah): If Reuven signed a document saying that he owes Shimon, Shimon collects from unsold property.

(Rav Yehudah citing Shmuel): The Halachah follows Chachamim.

Question: Why did he need to say this? The Halachah (normally) follows the majority!

Answer: The Halachah (normally) follows Rebbi when he argues with one Tana. One might have thought that the Halachah follows him even against a majority!

Question (Rav Chinena bar Chiya): Did Shmuel really say that the Halachah follows Chachamim?

There was a document validated in Shmuel's Beis Din that said that both witnesses confirmed both signatures!

Answer (Rav Yehudah): That document was of orphans;

Shmuel was extra careful to validate it in such a way that even if a Beis Din will mistakenly think that here the Halachah follows Rebbi against a majority, they will still accept the validation.

(Rav Yehudah citing Shmuel): A witness may join a judge. (If someone claims that a validated document was forged, it suffices for one witness to confirm his signature and one of the validating judges to confirm his signature.)

Rami bar Chama: What a wonderful teaching!

Rava: No! They do not join, since they testify about different matters! (This is like Chachamim, who say that a witness testifies about the content of the document.)

Rami bar Yechezkel: Do not heed these rules that my brother (Rav Yehudah) quotes in the name of Shmuel.

(Ravnoy citing Shmuel): A witness may join a judge.

Ameimar: What a wonderful teaching!

Rav Ashi: Because your grandfather (Rami bar Chama) praised it, also you praise it? Rava refuted it!

(Rav Safra quoting R. Aba): If three judges sat to validate a document and two of them recognize the signatures, before the two sign they testify about the signatures in front of the third judge. Then, all three sign the validation;

If the two judges signed before testifying, they may not testify to enable the third judge to sign.

Inference: The text of the validation may be written before the testimony.

Objection: Rav Papi taught that a validation that was written before testimony on the signatures is invalid, since it appears false;

Here too, it appears false (to write that all three judges knew the signatures before the third heard testimony)!

Correction: Rather, the two judges testify before writing the validation. If it was already written, they may not testify to enable the third judge to sign.

We learn three laws from this teaching;

A witness can act like a judge after testifying.

If the judges recognize the signatures, there is no need to testify in front of them.

If the judges do not recognize the signatures, testimony must be given in front of all of them.

Objection (Rav Ashi): I agree that we learn that a witness can become a judge (1);

However, we cannot learn that if the judges recognize the signatures, there is no need to testify in front of them (2). In R. Aba's case, there is some testimony in front of the third judge!

Also, we cannot learn that if the judges do not recognize the signatures, testimony must be given in front of all of them (3). R. Aba's case is different. If we do not testify in front of the third judge, no testimony is given at all!

Question (Rav Safra to R. Aba - Mishnah): If three members of the Beis Din that determines Rosh Chodesh saw the new moon, two of them stand. They seat two other judges of the Beis Din by the third, and the first two testify in front of them;

An individual cannot declare the new month. Rather, all three declare it.

If a witness could become a judge, (they would not need two more judges. Two would testify in front of the third, and) the three who saw could declare the new month!

Answer (R. Aba citing Rav): Declaration of the new month is mid'Oraisa, so for this a witness cannot become a judge. Validation of documents is mid'Rabanan, so for this a witness can become a judge.