Abaye asked Rava bar Sharshom 'Eima li Izi (my friend) Gufa de'Uvda Heicha Havi' when he heard the rumor - that he was 'eating land belonging to Yesomim'.

In response, he explained to Abaye the Mashkanta de'Sura that he received from their father had just expired. A Mashkanta de'Sura is - where the debtor gives the creditor a Mashkon to eat fruit for a fixed period of time as payment of the debt. And when the time expires, he returns the field and the debt is cancelled.

Rava bar Sharshom then continued to eat the fruit of the Yesomim - on the basis of another debt that, he claimed, their father owed him.

Rava bar Sharshom claimed that he had a 'Migu' - inasmuch as (bearing in mind that he had eaten the fruit for more than three years in the lifetime of the father) he could have hidden the Sh'tar Mashkanta and claimed that he had purchased the field from the father.

He was using the 'Migu' to try and spare himself - from having to swear (due to the principle 'ha'Ba Lipara mi'Nechsei Yesomim, Lo Yipara ela bi'Shevu'ah'.

However, Rava bar Sharshom would not have been obligated to swear even if he had claimed that he purchased the field - because a. a claim on Karka does not require a Shevu'ah, and b. because the Chazakah stands in place of a Sh'tar, which does not require a Shevu'ah either (see Tosfos DH 'Migu').

Abaye rejected Rava bar Sharshom's argument - on the grounds that his 'Migu' was unacceptable, since the Kol, which preceded the father's death, ought to have sufficed as a warning (like a Mecha'ah), to look after his Sh'tar.

He therefore instructed him - to return the field to the Yesomim and to claim it when they grew up.

He could not swear to the Yesomim immediately and claim his debt - because although Chazal permit claiming from Yesomim with a Shevu'ah, that is only after they grow-up; as long as they are Ketanim, the principle 'Ein Nizkakin le'Nechsei Yesomim Ela-im-Kein Ribis Ocheles bahen' applies (see Bach 6).

We reconcile Abaye, who authorized Rava bar Sharshom to claim from Yesomim from the time they reached the age of thirteen, with the Sugya in the last Perek, which delays their right to sell their father's property until the age of twenty - by confining the latter to the Din of selling for their own needs; whereas Abaye is speaking about paying of their father's debts.

The significance of the age of thirteen is - that prior to that, they are not Chayav to perform Mitzvos (and are therefore not subject to paying off their father's debts).

Abaye would have issued the same ruling (authorizing Rava bar Sharshom to claim from the Yesomim when they grew up) had the loan been an oral one ...

... based on Rav Papa's ruling at the end of the Masechta 'Milveh-al-Peh Govah min ha'Yorshim' (provided there are witnesses that the loan took place).

When a relative died leaving a date-palm, Rav Idi bar Avin claimed that he was the closest relation. Along came another man and claimed - that he was closer still.

When that man admitted that he was not as close a relative as he was - Rav Idi then demanded to be reimbursed for all the fruit that the man had eaten up to that time.

Rav Chisda rejected his claim outright - based on the principle of 'Kol de'Alim G'var' (the basis of the ruling of the current She'eilah).

He therefore argued - that since Rav Idi bar Avin had no proof that he was a closer relative than the man other than the latter's own admission, the man had until now eaten the fruits lawfully (based on 'Kol de'Alim G'var'), and now that he gave up the right, it was as if he had given Rav Idi a gift, which does not work retroactively.

Abaye and Rava maintained however - that the man's admission automatically worked retroactively and he was therefore obligated to pay Rav Idi for the fruit.

According to another text, which Rabeinu Chananel accepts, both parties brought witnesses that they were relatives of the deceased man, and Rav Chisda placed the tree in the possession of Rav Idi's rival, before the rival admitted that Rav Idi was the closer relative. The reason that ...

... Rav Chisda absolved the rival from paying for the fruit was - because the fact that he ultimately received the tree was due (not to Rav Idi's witnesses, who had not testified that he was a closer relative than his rival, only that they did not know who the rival was, but) to the admission of the latter, who had previously argued that he was a closer relative (as we explained in the first version [see also note in Rashbam]). Consequently, as far as the fruit was concerned, the rival had a 'Migu', since he could have claimed that he did not eat any fruit at all.

... Abaye and Rava disagreed with him was - because having admitted that he did eat the fruit, the principle 'Hoda'as Ba'al-Din ke'Me'ah Eidim Dami' (the admission of the owner is akin to hundred witnesses) applied, and he was obligated to pay.

And we reject this version - since it appears from the Sugya that the fruit that the rival ate was indeed subject to the witnesses' testimony, and not to his own admission.

In a case where Reuven and Shimon both claim that a field belonged to their respective parents, and Reuven brings witnesses to that effect, whereas Shimon brings witnesses that he had worked on it for three years ...

... Rav Chisda accepts Shimon's claim - because he has a 'Migu' (he could have claimed that he effected the Chazakah after having purchased it from Reuven).

... Abaye and Rava disagree with him on the grounds - that it is a'Migu be'Makom Eidim'.

The Halachah is - like Abaye and Rava.

When Reuven, who claimed that he had purchased a field from Shimon and that he had worked in it for three years, was only able to bring witnesses for two, Rav Nahman ruled - that he had to return the field and pay Shimon for the two years' fruit that he ate.

Rav Z'vid says that, had he claimed that he had only gone into the field for the fruit (either like an Aris [who tends the field for a half, a third or a quarter of the produce]) or that he had purchased the fruit for ten years, he would have been believed with a Shevu'as Hesses (mi'de'Rabbanan) ...

... with a 'Migu' (since he could have claimed that he ate only a little more than the expenses (which would still constitute a Chazakah, and which presumably, he would have to pay).

This case is different than the previous one, where, according to Abaye and Rava, Rav Idi bar Avin's rival had to pay for all the fruit - because whereas there, having admitted that the property belonged to Rav Idi bar Avin, the rival had eaten fruit that was definitely not his, here, although Reuven had to return the field for lack of proof that it was his, this does not prove that it was definitely not his (since the fact that Shimon is Muchzak in the field, does not prove that it does not belong to Reuven).

Rav Z'vid rules that if Reuven claims that he went down to the field for Peiros (as we just explained), he is believed, comparing it to statement of Rav Yehudah, who said that if Reuven takes a scythe and a rope and declares that he is going to climb the date-palm that Shimon sold him to pick dates, which he then does - he is believed, because a person would not have the Chutzpah to brazenly pick somebody else's fruit.

And the reason that we believe Reuven when he claims 'le'Peiros Yaradti' but not when he claims that the fruit is his because he purchased the field is - because in the latter case, the Chazakah that a person would not have the Chutzpah to go into a person's field and eat the fruit, is overridden by the fact that he does not produce a Sh'tar, whereas in the former, it is not customary to write a Sh'tar when buying only the fruit (or when undertaking to be an Aris).

When Reuven, who claimed that he had purchased a field from Shimon and that he had eaten its fruit for three years, was only able to bring one witness to that effect, the Rabbanan wanted to rule - that he was obligated to return the field, since his exemption depended on the Shevu'ah that he made to counter the witness's testimony, something that he was unable to do ...

... because he agreed with what he said.