Yevamot

and he who cohabits with her  is liable to bring an asham talui!  R. Shesheth replied:  When she was married, for instance, to one of her witnesses.  But she herself is liable to an asham talui!  — Where  she states, 'I am certain',  If so, what need was there to state [such an obvious ruling], when even R. Menahem son of R. Jose  maintained his view only where the witnesses  came first and the woman married afterwards, but not  where she married first and the witnesses came afterwards! For it was taught: If two witnesses state that he  was dead and two state that he was not dead, or if two state that the woman was divorced and two state that she was not divorced, the woman must not marry again, but if she married she need not leave;  R. Menahem, son of R. Jose, however, ruled that she must leave.  Said R. Menahem son of R. Jose, 'When do I rule that she must leave? Only when witnesses came first and she married afterwards, but where she married first and the witnesses came afterwards, she need not leave!'  — Rab also spoke of the case where witnesses came first and the woman married afterwards, [his object being] to exclude the ruling of R. Menahem son of R. Jose. Another reading: The reason then  is because she married first and the witnesses came afterwards,  but where witnesses came first and the woman married afterwards, she must leave. In accordance with whose [view is this ruling]? — In accordance with that of R. Menahem son of R. Jose. Raba raised an objection: Whence is it deduced that if [a priest] refused  he is to be compelled?  It was expressly stated, And thou shalt sanctify him,  even against his will. Now, how is this  to be understood?  If it be suggested [that it is a case] where she was not married to one of her witnesses  and she does not plead 'I am certain',  is there any need to state that he is to be compelled?  Consequently it must refer to a case  where she was married to one of her witnesses  and she pleads, 'I am certain'; I and yet it was stated that he was to be compelled;  from which it clearly follows that she is to be taken away from him!  — A priestly prohibition is different.  If you prefer I might say,  'What is the meaning of "he is to be compelled"? He is to be compelled by means of witnesses'.  And if you prefer I might say:  [It is a case] where witnesses came first and she married afterwards, and this represents the view of R. Menahem son of R. Jose.  R. Ashi replied. What is meant by the expression, 'She need not leave' which Rab used? She is not to depart from her first state of permissibility.  But surely Rab has said this once! For we learned, IF SHE MARRIED WITHOUT AN AUTHORIZATION SHE MAY RETURN TO HIM, and Rab Huna stated in the name of Rab: This is the established law!  — One was stated as an inference from, the other. Samuel said: This  was taught only in the case where she does not contradict him,  but where she contradicts him she need not leave. What [are the circumstances] spoken of? If it be suggested that there are two witnesses,  of what avail is her denial?  [It must then deal with the case] of one witness, and the reason  is because she contradicts him;  had she, however, remained silent, she would have been obliged to leave. But, surely, 'Ulla stated that 'wherever the Torah allows credence to one witness  he is regarded as two witnesses, and the evidence of one man  against that of two men has no validity!'  — Here it is a case of evidence by ineligible witnesses,  and [Samuel's statement is] in accordance with the view of R. Nehemiah. For it was taught: R. Nehemiah stated, 'Wherever the Torah allows credence to one witness  the majority of opinions is to be followed,  and [the evidence of] two women against that of one man is given the same validity as that of two men against one man'. And if you prefer I might reply: Wherever one eligible witness came first,  even a hundred women  are regarded as one witness;  here, however, we are dealing with a case where a woman witness came in the first instance;  and the statement of R. Nehemiah is to be explained thus: R. Nehemiah stated, 'Wherever the Torah allows credence to one witness, the majority of opinions is to be followed, and [the evidence of] two women against that of one woman is given the same validity as that of two men against one man, but that of two women against that of one man is regarded only as that of a half and a half. SHE ALSO REQUIRES A LETTER OF DIVORCE FROM ONE AS WELL AS FROM THE OTHER. It is quite intelligible that she should require a divorce from the first husband; but why also from the second [when their union was a] mere act of adultery?  — R. Huna replied: This  is a preventive measure against the possibility of assuming that the first had divorced her and the second had [lawfully] married her, and that consequently  a married woman  may leave her husband without a letter of divorce. If so,  in the latter clause also, where it was stated, 'If she was told "your husband is dead", and she was betrothed, and afterwards her husband came, she is permitted to return to him',  might it not be assumed there also that the first husband had divorced her and the other had [lawfully] betrothed her and that consequently a betrothed woman may be released without a letter of divorce! — As a matter of fact she does require a letter of divorce.  If so,  [it might there also be assumed that] the first had again married his divorced wife after she had been betrothed!  — [This statement is in] accordance with R. Jose b. Kiper who stated [that remarrying one's divorced wife] after a marriage  is forbidden but after a betrothal  is permitted.  Since, however, it was stated in the final clause, 'Although