Chapter 9, Mishnah 11. This mishnah is partly similar to the previous one, which also deals with a mix-up among Pesach offerings. The difference between them: the previous mishnah dealt with two groups whose offerings became mixed up, while our mishnah discusses two individuals, each of whom had a Pesach offering of his own.
The Case of the Mishnah:
Two men, each with his own Pesach offering, and the offerings became mixed up with one another so that it is not known which offering belongs to whom. How should they proceed?
This one pulls one animal toward himself and that one pulls one animal toward himself - each takes one of the two offerings for himself, even though he does not know whether it is his own offering.
Each of them registers a man from the marketplace together with him, an outsider, who joins him for his own Pesach offering - wherever it may be.
This creates a situation parallel to the previous mishnah: two groups, and in each group two men registered together for the same Pesach offering; except that it is not known where each offering is.
Now they can proceed just as they did in the previous mishnah: one of the two members of the first group moves over to the second group, and the other moves over to the first group, so that each one is registered for a group other than the one he was in originally.
The Wording of the Stipulation:
"Im sheli hu Pesach zeh - yadecha meshuchos mishelcha venimneisa al sheli" - if the offering we are standing before now is mine, then your hand is withdrawn from your own Pesach offering wherever it may be, and you are registered for mine.
"Ve'im shelcha hu Pesach zeh - yadai meshuchos mishel venimneisi al shelcha" - and if this offering is yours, then my hands are withdrawn from my own Pesach offering wherever it may be, and I am registered for yours.
In this way each of them ends up registered for the correct Pesach offering.
The Difficulty According to the View Requiring an Original Member:
This arrangement seemingly does not fit with the view that one of the original members must remain in the group, since it could end up that no one from the original members of the group remains registered for this particular Pesach offering.
Furthermore: the previous mishnah implies that if there were five groups, five men would be needed in each group - and this inference works well precisely according to the view that an original member is required. For if no original member is needed, that number is not necessary, since one could simply register a man from the marketplace. Yet our mishnah, which permits registering a man from the marketplace, implies otherwise.
The Gemara's Resolution:
The Gemara suggests that in the case of our mishnah the situation is different. The view that an original member is required is the view of Rabbi Yehudah, and in his opinion the Pesach offering is not slaughtered for an individual. Consequently, a person who was alone on a Pesach offering necessarily had to have another person join him from the outset according to Rabbi Yehudah. Therefore the person who ultimately joins him is considered one of the original members, since it was self-evident that another person would have to be registered, and it is as though he had been there from the start. It emerges that the arrangement works well even according to Rabbi Yehudah, who requires an original member: the new member is viewed as an original member, because according to Rabbi Yehudah the other member could not have been there alone.
In summary: in this mishnah we learned how two individuals whose Pesach offerings became mixed up should proceed: each pulls an offering toward himself, registers a man from the marketplace together with him, and afterward they each move over to the other's group and make a stipulation, so that each one is registered for his own offering. We also examined the difficulty according to the view that requires an original member, and the Gemara's resolution according to Rabbi Yehudah.