Yevamot

if  for any other woman, the letter of divorce has no validity,  because it was not in his power to divorce her.  Rami b. Hama inquired, however, what is the law if  for one's sister-in-law?  Is she, because she is bound to him,  regarded as his betrothed  or perhaps, since he addressed no ma'amar to her, she is not so regarded. This is undecided. R. Hanania inquired: What is the law if he  wrote a letter of divorce in respect of his levirate bond but not in respect of his ma'amar, or in respect of his ma'amar and not in respect of his levirate bond?  Is the ma'amar imposed upon the levirate bond,  so that the levir's action  is like that of divorcing half a woman,  and when a man divorces half a woman his action, surely, has no validity at all; or do they remain independent of one another?  — Might not this enquiry be solved by reference to Raba's ruling? For Raba ruled: If he  gave her a letter of divorce in respect of his ma'amar, her rival  is permitted!  — This was obvious to Raba; to R. Hanania, however, it was a matter of doubt. What, then, is the decision? — This remains undecided. IF THE LEVIR SUBMITTED TO HALIZAH AND THEN ADDRESSED TO HER A MA'AMAR. Rab Judah said in the name of Rab: This  is the view of R. Akiba who holds that betrothal with those whose intercourse involves the penalties of a negative precept is of no validity; the Sages, however, maintain that there is some validity in acts after halizah. But how can you ascribe it  to R. Akiba? In the first section, surely, it was stated, IF THE LEVIR GAVE HER A LETTER OF DIVORCE AND THEN ADDRESSED TO HER A MA'AMAR, IT IS NECESSARY FOR HER TO OBTAIN [A SECOND] LETTER OF DIVORCE AND TO PERFORM THE HALIZAH, while if [this Mishnah represented the view of] R. Akiba would a ma'amar to her be valid after a letter of divorce had already been given to her? Surely it was taught: R. Akiba said, 'Whence is it deduced that if a man gives a letter of divorce to his sister-in-law she is thereby forbidden to him for ever? Because it was stated Her former husband, who sent her away, may not [take her again to be his wife],  [i.e., immediately] after sending her away'!  R. Ashi replied: A divorce given by levirs is only Rabbinically valid,  and the Scriptural text is a mere prop. Likewise it was also taught: Rabbi said, this statement  was made only in accordance with the view of R. Akiba who treated a haluzah as a forbidden relative;  the Sages, however, maintain that there is some validity in acts after halizah; and I say, 'When [is betrothal after halizah valid]? Only when he betrothed her as in ordinary matrimony,  but if he betrothed her for levirate union,  there is no validity in any such act after the halizah. It was taught elsewhere: If a man submitted to halizah from his sister-in-law and then betrothed her, Rabbi said, 'If he betrothed her as in ordinary matrimony it is necessary for her to obtain from him a letter of divorce, but if as for a levirate union there is no need for her to obtain from him a letter of divorce'. The Sages, however, said: 'Whether he betrothed her as in ordinary matrimony or as for the levirate union it is necessary for her to obtain from him a letter of divorce'. Said R. Joseph: What is Rabbi's reason?  — It was given the same legal force as that of the action of a person digging in the estate of a proselyte  believing it to be his own,  which constitutes no kinyan.  Said Abaye to him:  Are the two cases alike? There  he  had no intention at all of acquiring possession,  but here  his intention, surely, was to acquire possession!  This, indeed, could only be compared to the case of a person who digs in the estate of one proselyte and believes it to be that of another, where he does acquire possession!  No, explained Abaye, here we are dealing with a case where the levir said to her, 'Be thou betrothed to me by the ma'amar of the levirate union'. Rabbi is of the opinion that the ma'amar can only be imposed upon the levirate bond,  but here  the halizah had already previously removed the levirate bond.  The Rabbis, however, are of the opinion that the one is independent of the other.  If, then, the levir had said to her at first,  'Be thou betrothed unto me by this ma'amar of the levirate union', would not his kinyan have been valid?  Consequently it is now also valid. Raba said: Had he said to her,  'By the ma'amar of the levirate union', there would be no disagreement [among the authorities] that it is valid; but here  we are dealing with a case where the levir said, 'Be thou betrothed unto me by the bond of the levirate'. Rabbi is of the opinion