Kommentar zu Ketubot 13:6

העורר על השדה וכו' – Reuven protests concerning the field that is in the hand of Shimon, and says to him: “Levi who sold it to you stole it from me, and he is inscribed on the bill of sale that Levi wrote to Shimon who sold it to him.

Introduction The fourth ruling stated by Admon is not connected at all to the issue of marriage, but rather has to deal with a person who signed on another person’s deed to a piece of land but later claims that the land is actually his own. Note that in this and the following mishnayoth, Admon disputes with the Sages and that Rabban Gamaliel is absent. It seems that this is a second collection of Admon’s sayings, joined by the editors of the Mishnah to the first.

אדמון אומר יכול הוא שיאמר – just as I did not protest at the time when you purchased this field from Levi and I signed/inscribed as a witness in the midst of the document because Levi is a strong man and difficult to remove something from his hand, it was pleasant for me that it should be in your hand than that I would [try] to remove it from you in court.

If a man contests [the ownership of] a field and he has signed as a witness on [its deed of sale], Admon says: He can say, “[Litigation with] the second is easier for me, since the first is a more difficult person than he”. But the Sages say: He lost his right. In this case Reuven claims that a piece of land that Shimon possesses is actually his. Shimon proves that the land is his by showing a sale document on which Reuven is signed as a witness. The deed says that Shimon bought the land from Levi. Shimon says that Reuven’s signature is de facto proof that he admits that the land is Shimon’s. According to Admon, Reuven may claim that he signed on the deed because he preferred to claim the land from Shimon than claim it from Levi. His signature on the deed is therefore not proof that he has admitted that the land belongs to Shimon. He can still bring other proof that the land belongs to him. The Sages disagree and state that the signature is proof of such an admission and therefore even if Reuven brings proof that the land actually belongs to him, he cannot reclaim it.

אבד את זכותו – for since and he signed, he admitted that he had no business with this, but the Halakha is not like Admon, and especially when he signed it as a witness, this is what Admon and the Sages were arguing about, but if he is signed as a judge to uphold the document, everyone agrees that he did not lose his right because he would be able to say: “I did not know what was written in the document for the judge who signs as the legal endorsement of a note, stating that it has been produced in court and found valid – to uphold the document and it is not necessary that he knew what was written in the document other than that he should recognize the signatures alone.

If [the protester] made it a boundary mark [when selling an adjacent piece of land to] another person he has lost his right [to protest]. In this cases, Reuven again claims that a piece of land that Shimon possesses actually belongs to him. However, Shimon brings a deed of sale for another piece of land, in which Reuven used the piece of land under dispute as a border marker for the property being sold. Reuven would not have used this piece of land as a border marker had he thought the land belonged to him himself. Since in this case Reuven cannot say he did so because litigation with the second is easier, he has lost his right to make a claim.