(Mishnah): If they do not recognize the witness, they (the Beis Din of his town) send another person with him to vouch for his validity.

Originally, they would accept testimony for the New Moon from any person. When the heretics began to sabotage things (by testifying falsely), Chazal decreed that they would only accept people who were recognized by the Beis Din.

Originally, they would wave torches. When the Kutim began to sabotage things (by waving torches at the wrong time), Chazal decreed that messengers would be sent out.

(Gemara - R. Yona): The Mishnah should read as follows - Originally, they would accept testimony of the New Moon from any person. If they would not recognize him, they would send another person with him (to vouch for him).

R. Yosa: One could retain the original text of the Mishnah and it could be read as follows - If they do not recognize him, they send another person with him. Why is this necessary? (Why can we not trust any person that comes to testify?) Because originally they would accept testimony from any person...etc.

Question: Is only one witness believed to vouch for this witness?

Answer: Chazal were lenient (to require only one witness) within their stringency (to require any verification of the validity of this witness).

Question: Is one witness believed like two? What is the case? If there were two, one person testifies on both his own and the other witness's signature and the other witness is absent. (Can we use the first witness and another person to testify on the second witness's signature)?

Answer (R. Zeira/Rav Chuna quoting Rav): He and another cannot combine to testify on the signature of the second witness.

The question is when there are two people - all recognize one of them but nobody recognizes the other one.

R. Yudan: This is correct. If two people left a town, like Susita, that is inhabited mostly by gentiles and everyone recognizes the first one as Jewish but nobody recognizes the second one - if the other witness recognizes him, can he join with another person to testify about the second witness?

If you say yes, is the entire testimony not dependant on one person?! Here also, it is the same problem.

Mishnah (in Maseches Yoma): "The appointed one said to them - go out and see if the time for slaughtering has arrived. If it arrived, the observer said, 'Birkai'" What is Birkai? Barak Birkai. What is Barak Birkai? The luminary (sun) has brought light.

Is only witness believed (to testify about the time of slaughtering)? Yes, because it is a fact that is easily verified.

Question: Why is it easily verified? (Perhaps by the time someone else goes up to verify if the sun had dawned, the sun will dawn!)

Answer: It is still possible to say how long ago the sun dawned -whether just now or earlier.

If one witness said that a certain baby was born on Shabbos, we may circumcise him the following Shabbos. If the witness said that it is already nightfall, we may take out items into the public domain

R. Ami carried based on the testimony of the women who were drawing water from the well. R. Matanya carried based on the testimony of the farmers of Ivrisa.

R. Imi circumcised on Shabbos based on the testimony of women who said that the baby was born before the sun set over Susita.

Query: When one or several people recognize the witnesses, may they also profane the Shabbos in order to come to Beis Din to testify?

Answer: R. Nehurai said - Once on Shabbos, I descended to Usha to testify about a witness. I was not certain that they would need me to testify, but it gave me good reason to go to Usha and I was therefore able to meet my great Rav there.