Bava Batra

that a man is at liberty to renounce beforehand  an inheritance which is likely to accrue to him from another place;  and this rule again is based on the dictum of Raba, that if anyone says, I do not desire to avail myself of a regulation of the Rabbis of this kind, we comply with his desire.  To what was Raba referring  when he said 'of this kind'? — He was referring to the statement made by R. Huna in the name of Rab: A woman is at liberty to say to her husband, You need not keep me and I will not work for you. [Since the Mishnah says that a husband has no hazakah in the property of his wife, we infer that] if he has proof [that she sold it to him],  the sale is effective. [Yet why should this be?] Cannot she say [in this case also], I merely wished to oblige my husband?  Have we not learnt: If a man buys [a field] from the husband  and then buys it again from the wife, the purchase [from the wife] Is void?  This shows that she can say: I merely consented in order to oblige my husband, and cannot she say here also that she merely wished to oblige her husband? — The truth is that this [Mishnah] has been qualified by the gloss of Rabbah son of R. Huna: The rule really required to be stated in reference to those three fields [that are specially allotted to her]  — one that the husband inserted In the kethubah,