R. Yosi says, this applies only to capital cases. In monetary cases, the testimony of the Kosher witnesses is valid. (Rashi - due to "v'Hitzilu ha'Edah", we seek reasons to acquit in capital cases. Tosfos - in capital cases, if one of the two witnesses is Karov or Pasul, the remaining witness is worthless, but in monetary cases, the remaining witness obligates an oath.)

Rebbi says, this applies both to capital and monetary cases;

This is only if the witnesses warned the transgressor (i.e. they intended to be witnesses). If you will not say so, if two brothers see a murder (even with other witnesses), Beis Din will be unable to kill the murderer (because one of the witnesses is related to another)!

(Gemara - Rava): (They are considered one Kat of witnesses) only if they all testified Toch Kedei Dibur.

Question (Rav Acha mi'Difti): Toch Kedei Dibur is the time needed for a Talmid to greet his Rebbi (to say three or four words, Shalom Alecha Rebbi (u'Mori)). A hundred witnesses cannot testify within this time!

Answer (Ravina): It suffices if each begins within Toch Kedei Dibur of the previous one.

(Mishnah - R. Akiva): (... Also if one of three witnesses was found to be a relative or Pasul, the testimony is invalid.)

Question (Rav Papa): A murder victim was an invalid witness. We should say that he disqualifies all the witnesses!

Answer #1 (Abaye): Yes! According to R. Akiva, the testimony is valid only if he was killed from the back (and did not see the murder).

Question (Rav Papa): A Nirva (the 'receiving' party in homosexual relatiions) is an invalid witness. He should disqualify the witnesses!

Answer #1 (Abaye): The testimony is valid only if he was facing away (and did not see the Shochev (the man who had Bi'ah with him)).

Question (Rav Papa): The murderer or the Shochev should disqualify the witnesses!

Abaye was silent.

Answer (and Answer #2 to the previous questions - Rava): "Yakum Davar" - witnesses are those who establish (the truth of) a matter, and not the parties that do the matter. (The parties are not considered witnesses at all.)

(Mishnah - R. Yosi): This applies only... (Rebbi says, this is only if they warned the transgressor... )

Version #1 - Rashi - Question: What do we ask the invalid witnesses ((Tosfos - in monetary cases) to determine whether or not they intended to be witnesses)?

Answer (Rava): We ask them if they came to the scene of the incident just to see, or in order to testify about it later (Tosfos, R. Chananel; Ritva - we ask them whether they came to Beis Din to testify, or just to see what the outcome will be).

Version #2 - R. Chaim Kohen - Question: What do we ask the valid witnesses?

Answer (Rava): We ask them if they came to Beis Din intending to testify with the invalid witnesses.

(Rav Yehudah): The Halachah follows R. Yosi.

(Rav Nachman): The Halachah follows Rebbi.

(Mishnah): If two witnesses saw the murderer from a window, and two witnesses saw from a different window, and someone in the middle warned him:

If at least one witness in each pair saw one of the other pair, they are considered one Kat. If not, they are two Kitos.

Therefore (when they are two Kitos), if one Kat was Huzam, they and the murderer are killed, and the other Kat is exempt.

R. Yosi says, if both witnesses did not warn him, (he is exempt, therefore also) the witnesses are not killed - "Al Pi Shnayim Edim."

This also teaches that Sanhedrin must hear the testimony of the witnesses themselves, and not through a translator.

(Gemara - Rav Zutra bar Tuvya) Question: What is the source that Edus Meyuchedes (when the witnesses did not see each other) is invalid?

Answer: "Lo Yumas Al Pi Ed Echad";

Question: What does 'Echad' mean?

Suggestion: There is only one witness.

Rejection: We already know this from "Al Pi Shnayim Edim"!

Answer: It means that the witnesses are one by one, i.e. they did not see each other.

Support (Beraisa): "Lo Yumas Al Pi Ed Echad" teaches that if one witness saw from a window, and another witness saw from a different window, they do not join;

Even if they saw from the same window, one after the other, they do not join.

Question (Rav Papa): The Tana taught that when they see from different windows, each saw the entire incident, yet they do not join. If they saw from the same window, each saw only part of the incident. All the more so they do not join! (What is the Chidush of the Seifa?)

Answer (Abaye): The Chidush is regarding Arayos, for each saw a full act that is Chayav Misah.

(Rava): If the witnesses saw the Masreh (the one who gave warning), or if the Masreh saw them, the witnesses join. (Tosfos - in the latter case, we must know through (other) witnesses that the Masreh saw them.)

(Rava): The warning can be even by himself (Rashi - the victim warned him; Kesef Mishnah - the transgressor said 'I know that Beis Din will kill me for this') or by a Shed.

(Rav Nachman): "Lo Yumas Al Pi Ed Echad" - Edus Meyuchedes is invalid for capital cases, but it is valid for monetary cases.

Question (Rav Zutra): (We rely on any possible reason to avoid killing a transgressor.) If Edus Meyuchedes is valid in some case, we should validate it in capital cases when it will save the transgressor! (If we consider all the witnesses to be one Kat, if even one is Huzam, all the testimony is invalid!) Why does the Mishnah say that we kill the transgressor and the lying witnesses?

This is left difficult.

(Mishnah - R. Yosi): If both witnesses did not warn him (no one is killed).

Question (Rav Papa): R. Yosi does not require warning of two witnesses!

(Mishnah): If Reuven hated Ploni and he (seemingly accidentally) killed Ploni, he is killed, for surely he was Mezid!

Answer (Abaye): The Tana of that Mishnah is really R. Yosi bar Yehudah.

(Beraisa - R. Yosi b'Rebbi Yehudah): A Chaver need not be warned, for warning is only to distinguish whether one is Shogeg or Mezid.

(Mishnah): This also teaches that the Sanhedrin may not hear the testimony of the witnesses through a translator.

Witnesses (Rambam - two parties) came in front of Rava. They did not speak a language that the judges knew; so he put a translator between them.

Question: The Mishnah forbids this!

Answer: Rava could understand what they said. He needed the translator only to speak to them.