Yevamot

and let the land remain in the possession of the lunatic! — Rather, said Abaye. Its friend telleth concerning it:  that which was taught in connection with betrothal  is also to be applied to divorce,  and what was taught in connection with divorce  is also to be applied to betrothal. Said Raba to him: If its friend telleth concerning it' what was the object of stating THIS IS?  -Rather, said Raba, whatever is applicable to betrothal  is also to be applied to divorce, but certain points are applicable to divorce,  which cannot be applied to betrothal. And THIS IS  which was mentioned in the case of divorce is not to be taken literally. as THIS IS was used in connection with betrothal  only because it was also used in connection with divorce. What was THIS IS mentioned in connection with betrothal meant to exclude? — To exclude the question of date which is inapplicable to betrothal.  And wherefore was no date ordained to be entered in [documents of] betrothal? This  may well be satisfactorily explained according to him who holds [that the date is required In a letter of divorce]  on account of the usufruct,  since a betrothed woman has no [need to reclaim] usufruct — 14 According to him, however, who holds [that it  was ordained] on account of one's sister's daughter.  the insertion of a date should have been ordained [in the case of betrothal also]!  — Since some men betroth with money  and others betroth with a document the Rabbis did not ordain the inclusion of a date. Said R. Aha son of R. Joseph to R. Ashi: What about the case of a slave of whom some acquire possession by means of money and others by means of a deed, yet the inclusion of a date has nevertheless been ordained by the Rabbis! — In that case  acquisition is generally by means of a deed; here,  it is generally by means of money. If you prefer I might say: Because it is impossible.  For how should one proceed? Were it  to be left with her, she might erase it.  Were it  to be left with him, it might happen that the betrothed might be his sister's daughter and he would shield her.  Were it to be left with the witnesses-well, if they remember  they could come and tender their evidence;  and if they do not,  they may sometimes consult the document and then come and tender evidence, while the All Merciful said, 'out of their mouth'  but not out of their writing. If so, let the same argument  be applied to divorce also! — There,  it  comes to save her,  here,  it  comes to condemn her. MISHNAH. IN THE CASE WHERE THREE BROTHERS WERE MARRIED TO THREE WOMEN WHO WERE STRANGERS [TO ONE ANOTHER]. AND ONE OF THEM HAVING DIED  THE SECOND BROTHER ADDRESSED TO HER  A MA'AMAR  AND DIED, BEHOLD, THESE  MUST PERFORM HALIZAH  BUT MAY NOT BE TAKEN IN LEVIRATE MARRIAGE; FOR IT IS SAID. AND ONE OF THEM DIED [ETC.] HER HUSBAND'S BROTHER SHALL GO IN UNTO HER.  ONLY SHE WHO IS BOUND TO ONE LEVIR  BUT NOT SHE WHO IS BOUND TO TWO LEVIRS.  R. SIMEON SAID: HE MAY TAKE IN LEVIRATE MARRIAGE WHICHEVER OF THESE HE WISHES  AND THEN PARTICIPATE IN THE HALIZAH WITH THE OTHER. GEMARA. If, however, the levirate bond with two levirs  is Pentateuchal,  even halizah should not be required! — But it  is only Rabbinical,  a preventive measure having been enacted against the possible assumption that two sisters-in-law coming from the same house  may both be taken in levirate marriage. Then let one be taken in levirate marriage and the other be required to perform halizah! — A preventive measure has been enacted against the possible assumption that one house was partially built