- One can inherit his grandfather directly, not through his father
A ruling was sent from Eretz Yisroel, which is emended to be: if someone sold his father’s property, but died during the father’s lifetime, בנו מוציא מיד הלקוחות – [the son’s] son can take the property from the purchasers after his grandfather dies, וזו היא שקשה בדיני ממונות – and this is something difficult to understand among monetary matters. The apparent difficulty is that the purchasers should tell the grandson: אבוך מזבין ואת מפיק – “Your father sold us the property, and you are taking it from us?! How can you inherit what your father sold?” The Gemara questions this difficulty, suggesting the grandson can tell the purchasers: מכח אבוה דאבא קאתינא – “I am coming to inherit from my grandfather directly, not from my father,” so the father’s sale is ineffective. This perspective is supported by the passuk: תחת אבותיך יהיו בניך תשיתמו לשרים בכל הארץ – in place of your fathers shall be your sons, you shall appoint them as officials throughout the land. This indicates that a son takes his father’s place to inherit the grandfather. The Gemara will eventually explain the difficulty, that perhaps the passuk is only a berachah to have inheriting descendants, and not teaching a law. Because this law is not taught outright, it is described as difficult.
- Relatives cannot testify because of a גזירת מלך
The Gemara suggests a case for the “difficult to understand among דיני ממונות”: if one signed a document of testimony for someone, ונעשה חתנו – and then became his son-in-law, he cannot authenticate his own signature, since he is now disqualified from testifying about his relative, but others can confirm his signature. The difficulty is: הוא לא מהימן אחריני מהימני – he is not believed about his signature, yet others are believed? If he is suspected to testify falsely for his father-in-law, perhaps he signed the document after becoming a relative and predated it!?
The Gemara concludes that this is not difficult: דלמא גזירת מלך היא – perhaps it is a decree of the King (Hashem) that he cannot testify about his relative while others can, ולאו משום דמשקר – and not because [the relative] is suspected to lie. If you do not say so, then משה ואהרן לחותנם – Moshe and Aharon, who cannot testify about their father-in-law, משום דלא מהימני הוא – is this because they are not believed to be truthful?! Rather, it must be a Divine decree disqualifying testimony about relatives.
- The incident of one who sold "נכסי דבר סיסין"
There was a person who told someone: נכסי דבר סיסין מזבנינא לך – “I am selling you the property of Bar Sissin” (i.e., properties I bought from him). There was a property in his estate called "דבי בר סיסין" – of the Bar Sissin estate, but the seller claimed it was not actually from Bar Sissin, but it was merely called that, and not included in the sale. Rav Nachman established the land in the buyer’s possession, requiring the seller to prove it was not truly Bar Sissin’s property. Rav objected that the law should be המוציא מחבירו עליו הראיה – the one seeking to take property from his fellow, the burden of proof is upon him. The buyer, who is attempting to take property held by its previous owner, must prove his case.
The Gemara poses a contradiction of both opinions from the case of the disputed three-year chazakah of "שכוני גוואי", and in its answer, explains Rav Nachman’s reasoning here, that since the owner said he was selling Bar Sissin’s properties, and this property is called “דבי בר סיסין,” the seller must prove it is not actually from that estate.