We already quoted Rav Safra 'Ein Kosvin Sh'nei Sh'taros al Sadeh Achas'. He says it - in order to explain the Beraisa currently under discussion 'Chutz me'Acharayus she'bo'.

Despite the fact that the purchaser already paid the creditor who claimed the field from him, he will be able to claim again from other purchasers who purchased who bought after him - by asking the creditor (after he has already received written permission from Beis-Din to claim) to postpone taking payment from him for another few years until the property is established as being his, and then, when the creditor does come to claim, he will use his other Sh'tar to claim the field again from the other purchasers, and share the profits with the creditor.

We have a problem however, with the fact that the creditor is able to claim again later, from Rav Nachman's statement concerning ...

... a 'Tirfa' - a written authorization from Beis-Din of the debtor's town to search the debtor's property for a suitable field to claim in lieu of his debt, either from B'nei Chorin or from Meshubadim, which he shows the Beis-Din of that town.

... an 'Adrachta' - a written power of attorney from Beis-Din authorizing him to actually seize the property that he decides upon.

... a 'Shuma' - a Sh'tar written by Beis-Din assessing the value of authorization from Beis-Din to take ownership of the property following the Beis-Din's assessment of its value.

The purpose of the Shuma is - to enable the debtor to redeem his land by paying the creditor the amount written on the Shtar.

Rav Nachman said that - unless Beis-Din state clearly in each subsequent Sh'tar that the previous one has been torn up, it is not valid.

The problem therefore is - how we can permit the creditor to claim from the purchaser without Beis-Din tearing the Sh'tar (to prevent him from claiming again, like Rav Nachman taught).

The Beraisa (and Rav Safra) is therefore not worried about the creditor claiming from the purchaser twice - but about a Nigzal, who brings witnesses that the seller who sold the field had stolen it from his father.

After Beis-Din write him a Sh'tar authorizing him to claim from subsequent purchasers, we are afraid - that he will make a Kenunya with the original owner's son to leave him the field. And then after four or five years, to claim it again, so that Beis-Din will repeat their original ruling, authorizing the purchaser to claim again from the subsequent purchasers.

When Rav Acha from Difti asked Ravina why the purchaser needed to ask the creditor to postpone his claim, he meant to ask - why we are not afraid that, once he has claimed from the one purchaser, the Nigzal will agree to claim from him again immediately in another Beis-Din, after which, he will claim from another purchaser with his second Sh'tar, and give the Nigzal half.

Ravina replied - that although technically, Rav Acha was correct, a person would be unlikely to do that, as it would involve two consecutive court-cases, inviting more people to investigate his affairs, and increasing his chances of being discovered.

We query even Ravina's explanation however - seeing as it would be possible to block the purchaser's second claim, by writing a receipt for the seller, stating that the purchaser lost the first Sh'tar, and that having claimed from the second purchaser with his second Sh'tar, he has no further claims against him (not B'nei-Chorin and not Meshubadim).

The Rabbanan in the presence of Rav Papa (or Rav Ashi) extrapolated from the previous Kashya that - we do not write a receipt ('Ein Kosvin Shover'), so as not to force the debtor to look after it against mice and the likes (placing the onus on the Ba'al ha'Sh'tar to look after his Sh'tar).

Rav Papa (or Rav Ashi) disagrees. He holds that as a rule, 'Kosvin Shover', and the reason that we do not write one here is - because it is the debtor who holds the receipt, and not the purchaser. And by the time the latter discovers that the money has already been paid, the first purchaser will have already claimed the land and eaten the fruit (and once something is stolen, it is difficult to retrieve).

When we say 'I Nami, le'Loke'ach she'Lo be'Acharayus', we mean that - he may even have purchased the field without Acharayus, in which case, he will not take the trouble to approach the seller, and will never find out that he has a receipt.

Nevertheless, we write a receipt in the case of a loan - because there, we say, the purchaser knows that since the borrower owes the creditor money, before relinquishing his land, he will check whether the debtor did not come to terms with the creditor.

We do not say the same here (in the case of a purchaser) - because, since the seller owes the purchaser land (and not money), the second purchaser does not expect the latter to have settled for money, and relinquishes his land immediately.

We learned in the Beraisa that if someone claims that he lost a Sh'tar Mekach u'Memkar, they write him a new one 'Chutz min ha'Acharayus', which Rav Nachman explains to mean that - they must specifically write that with this Sh'tar one may neither claim B'nei Chorin nor Meshubadin (becaue its sole function is to prove the sale).

Rafram extrapolates from there - that if he were to write nothing, he would nevertheless be able to claim Meshubadim, because of the principle 'Acharayus Ta'us Sofer hu' (failure to insert Acharayus in a Sh'tar is a Sofer's error).

Rav Ashi however, disagrees with Rav Nachman (and Rafram). According to him, the Beraisa means that - the Sofer does not insert Acharayus (because he holds 'Acharayus La'av Ta'us Sofer Hu'), and if it was not stipulated, then it is not meant to be there.

In a case where a woman gave a man money to purchase a field on her behalf - he went and bought her the field without Acharayus.

The woman claimed - that she appointed him a Shali'ach for her benefit and not for her detriment (and that consequently, the sale was invalid).

Rav Nachman therefore ruled that - the Shali'ach was obligated to repurchase the field from the seller without Acharayus in his own name, and to sell it to the woman with Acharayus.

We already cited the Beraisa in which Rabban Shimon ben Gamliel holds that when a Sh'tar Matanah is returned, the Matanah goes back with it. Rabah objects to Rav Asi's explanation that when Reuven gives Shimon a gift together with a Sh'tar, it is as if he stipulated that the gift is his only as long as he has the Sh'tar - because if that were so, Rabban Shimon ben Gamliel's ruling ought to extend to where the Sh'tar is stolen or lost, and should not be confined to where the beneficiary returns the Sh'tar.

In fact, Rabah explains, Rabban Shimon ben Gamliel and the Chachamim argue over whether 'Osiyos Niknos bi'Mesirah' (Rabban Shimon ben Gamliel) or not (the Rabbanan), as we explained earlier - and the Machlokes also extends to the Sh'tar of a sale.

Rabeinu Chananel rules like the Chachamim, based on the principle 'Yachid ve'Rabim, Halachah ke'Rabim'. Nevertheless, the Halachah might be like Rabban Shimon ben Gamliel - because that is the opinion of Rav Papa (or Ameimar) and Rav Ashi in ha'Mocher es ha'Sefinah, and it also appears to be the opinion of Abaye and Rava later in this Perek.

The basis of their Machlokes is - whether words on paper are better than spoken words, which are not subject to a Kinyan (Rabban Shimon ben Gamliel), or not (the Chachamim).