The Gemora inquires: Would we execute someone by stoning (if she has relations with a man) based upon the father’s testimony (that he married her off)?
Rav said: We would not. We only believe the father with respect to a prohibition, but not for execution. Rav Assi said: We would. We believe the father for everything.
Rav Assi admits that if she would say, “I got married,” we would not stone anyone.
Rav Assi notes the apparent contradiction in his rulings: If in a case (the father said that he married her off) where we believe a man that he is able to marry her (if he comes saying that he was the one who married her), and we rule that we would execute someone by stoning (for having relations with this woman). Then, in a case (where she was the one who said that she got married) where we do not believe a man to marry her (if he comes saying that he was the one who married her), shouldn’t the halachah certainly be that we would execute someone by stoning (for having relations with this woman)!?
Rav Assi answers: There is a clear distinction. The Torah believed the father, but not her. [The only reason that she is forbidden to every man is because of the principle of “shavya anafshei chaticha d’issura” i.e. she has made for herself a forbidden piece; she is compelled to abide by her declaration.]
The Maharik (shoresh 33) writes concerning a case where one witness testifies that a certain shochet was slaughtering improperly and the shochet himself contradicts the witness; since the witness is not believed, he himself is permitted to eat all future meat slaughtered by this shochet. This is not comparable to a case where a witness testifies regarding wine that is forbidden on account of it being yayin nesech because here there is a possibility that the shochet will repent and slaughter properly.
The Pri Chadash (Y.D. 1, 14) asks: Why don’t we apply the principle of “shavya a’nafshei chaticha d’issura,” one who states that something is forbidden, even if he is not believed in respect to everyone else, renders the object forbidden to him (as is evident from the Gemora in Kesuvos 9a)? All the meat slaughtered by this shochet should be forbidden to this witness!?
The Pri Megadim (Sifsei Daas, ibid, 41) answers that the Maharik is referring to a case where the witness retracted and said that he had testified falsely. In such cases, the principle of “shavya a’nafshei chaticha d’issura” does not apply.
Rav Elyashiv answers: The reason why one can render the object forbidden with the principle of “shavya a’nafshei” is not because he is believed in respect to himself; rather, it is because it is regarded as an oath. The witness is taking a vow forbidding himself from this particular object. Accordingly, he explains that the witness who testified regarding the shochet it making a vow that he will not eat the meat from this animal, however, he will not be prohibited, on account of his vow, against eating from any other animal that this shochet slaughters.
The Mishna Lemelech (Hilchos Shechitah 1:26) challenges the ruling of the Maharik from a Gemora (Kesuvos 44a) which discusses a case where two deeds were given over regarding the same field. The ruling is that the second deed cancels the first one. Rafram explains that the recipient has admitted to the other that the first deed is invalid. Accordingly, the Gemora continues that these witnesses must be regarded as legally unfit for further evidence concerning this recipient since he is stating that they put their signatures to an invalid document. We do not say that they should be valid witnesses later, for perhaps they repented. What is the difference between the two cases?
The Shaar Hamishpat (92:7) answers: The Maharik rules that all meat slaughtered by this shochet will be permitted to eat by the witness because there is a double doubt; perhaps, he has slaughtered the animal properly and perhaps he repented. Just because he slaughtered improperly (according to the witness’ testimony) one time, it is not logical that we should prohibit his slaughtered meat forever. However, in respect to testimony, once the recipient has stated that these witnesses testified falsely, they will be disqualified to offer testimony for him forever. Even according to those that hold that we can apply the principle of a double doubt in regards to monetary judgments, here, it will not apply. What can be said? Perhaps the witnesses will testify truthfully and perhaps they repented. This logic is not applicable by testimony, for testimony functions as a proof, and if we are uncertain if the witnesses repented or not, they cannot be accepted as witnesses because we have no proof that they are testifying truthfully. Therefore, they will not be believed for all future testimonies regarding this recipient.