As, if it enters your mind that it is prohibited by Torah law the mishna here would be difficult, for as soon as he slaughtered the animal a bit, at the very start of the act of slaughter, he has prohibited the animal, with regard to deriving benefit, as a non-sacred animal slaughtered in the Temple courtyard. When he slaughters the other part it is already prohibited with regard to deriving benefit, which means that it is not an animal that belongs to its owner that he slaughters.

Rav Aḥa, son of Rava, said to Rav Ḥavivi: It is possible to explain the mishna even according to the opinion that the halakhic ramifications of slaughtering are in effect throughout the slaughter, and even if one maintains that it is prohibited by Torah law to benefit from a non-sacred animal slaughtered in the Temple. As, when does the thief become obligated to pay the fourfold or fivefold payment as well? It is when he performs that first bit of slaughter in the beginning, before the animal becomes forbidden. Rav Ashi said to Rav Huna: Do not dismiss Rav Ḥavivi’s suggestion with this explanation. The verse: “If a man steal an ox or a sheep, and slaughter it” (Exodus 21:37), indicates that in order to impose liability to pay the fourfold or fivefold payment we require that the thief slaughtered it completely, and after having slaughtered it just a bit there is no complete slaughter yet.

Rav Huna said to Rav Ashi: But if you are correct, the mishna is difficult. Rav Ashi said to Rav Huna: This is what Rav Gamda said in the name of Rava: When does the mishna state that the thief is obligated to pay the fourfold or fivefold payment? It is in a case where the thief slaughtered part of the simanim outside the Temple, and finished slaughtering them inside the Temple. Therefore, the animal became prohibited with regard to deriving benefit only at the final stage of slaughter, concomitant with the liability to pay the fourfold or fivefold payment.

MISHNA: If one stole an ox or a sheep, as established based on the testimony of two witnesses, and he subsequently slaughtered the animal or sold it, also based on the testimony of the same witnesses, and these witnesses were found to be conspiring witnesses, these witnesses pay everything, i.e., not only the principal amount but also the fourfold or fivefold payment. This is in accordance with the Torah’s decree with regard to conspiring witnesses: “You shall do to him as he had conspired to do to his brother” (Deuteronomy 19:19). Since these witnesses attempted to obligate the alleged thief to pay the fourfold or fivefold payment, they themselves must pay that full amount.

With regard to one who stole an ox or a sheep, as established based on the testimony of two witnesses, and he subsequently slaughtered the animal or sold it, based on the testimony of two other witnesses, if both these witnesses and those witnesses were found to be conspiring witnesses, the first set of witnesses, who testified about the theft of the animal, pay the alleged thief the double payment, which is what they had conspired to cause him to pay. And the last set of witnesses, who attested to the slaughter or sale of the animal, pay the alleged thief a twofold payment for a sheep or a threefold payment for an ox, which they had conspired to cause him to pay over and above the double payment.

If only the witnesses in the last set were found to be conspiring witnesses, while the testimony about the theft remains intact, the thief pays the double payment to the animal’s owner and the second set of witnesses pay the alleged thief the twofold or threefold payment, the amount over and above the double payment, which is what they had conspired to cause him to pay.

If only one individual from the last set of witnesses was found to be a conspiring witness, the second testimony is nullified, as it was not submitted by two valid witnesses, whereas the first testimony remains intact. If one individual from the first set of witnesses is found to be a conspiring witness, the entire testimony concerning the thief is nullified. The reason is that if there is no theft established by reliable testimony there is no liability for slaughtering the animal and there is no liability for selling it.

GEMARA: One who is rendered a conspiring witness is barred from providing testimony in the future. The Gemara cites a fundamental dispute with regard to this disqualification. It was stated concerning a conspiring witness: Abaye says: He is disqualified retroactively, from when he provided his testimony. Any testimony he may have provided after that point in time is retroactively nullified. Rava says: He is disqualified only from that point forward, i.e., from when he was established to be a conspiring witness, but not retroactively from when he provided his testimony.

The Gemara explains the reasons for the two opinions: Abaye says he is disqualified retroactively because it is from that time when he testified that he is considered a wicked man, and the Torah said: “Do not put your hand with the wicked to be an unrighteous witness” (Exodus 23:1), which is interpreted to mean: Do not allow a wicked man to serve as a witness.

Rava says that he is disqualified only from that point forward because the disqualification of a conspiring witness is a novelty, i.e., it is not based on logic. The reason is that this is a case of two witnesses against two other witnesses, in which case neither testimony should be accepted. What did you see that causes you to listen to the second set of witnesses, who testify that the first set were not at the scene of the purported event? You could instead listen to the first set of witnesses, who testify to the event, and disbelieve the second set. Yet the Torah teaches that the second set of witnesses is always deemed credible and the first set is subjected to punishment as conspiring witnesses.

Therefore, as the disqualification of the conspiring witnesses is an anomaly, you have the right to disqualify them only from the time of the novelty and onward, i.e., this counterintuitive disqualification is not applied retroactively.

There are those who say that Rava also holds like Abaye, who says that by rights a conspiring witness should be disqualified retroactively from when he provided his testimony, and here this is Rava’s reason for not disqualifying him retroactively: