Pesachim, Chapter Seven, Mishnah 12. In the previous mishnah we dealt with the prohibition against breaking a bone of the korban Pesach. Our mishnah raises an interesting problem that arises regarding a possible breaking of a bone.
"Ever sheyatza miktzato":
The case is a limb of the korban Pesach that went out beyond its boundary, that is, outside the demarcation line of the place where it may be eaten. For example, on Erev Pesach, the limb went outside Jerusalem: this is an area where the offering may not be, since it must be eaten within Jerusalem, and once it has been taken out it becomes disqualified and must be burned.
What is the law when only part of the limb went out, while part of it remained inside the boundary? The part that stayed inside is fit to be eaten, and the part outside must be burned. But the question is: how does one separate them without breaking the bone?
To this the mishnah responds with a sequence of steps:
"Chotech ad shemagia la'etzem" - he cuts the flesh until he reaches the bone.
"Vekolef... ad shemagia laperek" - he peels back the flesh that remained inside the boundary, until he reaches the joint.
"Vechotech" - he cuts at the joint itself. This cutting is permitted, since it involves no breaking of a bone at all, only the severing of the connecting sinews. In this way he can take the flesh and the bone that are outside and burn them.
Some understand that the bone itself is not actually burned, only the flesh on it. However, this depends on whether it contains marrow, which is considered like flesh, in which case the bone too certainly requires burning. In any case, in this manner the portion that went outside its boundary and requires burning has been removed, and the problem of breaking the bone in the process has been avoided.
"Uvamukdashin":
By contrast, with mukdashin - the other offerings that are not the korban Pesach - there is no prohibition against breaking a bone, and therefore the law is straightforward: "Kotzetz bekufitz" - he chops the limb with a cleaver, even though he will thereby break the bone, "she'ein bo mishum shevirat ha'etzem" - there is no concern here of breaking a bone, since this prohibition does not apply to them at all.
Where does the boundary line of going outside the enclosure run?
The agaf is the part of the doorway that stops the door from swinging further - that projection which juts into the opening and halts the door. With regard to it the mishnah rules:
"Min ha'agaf ulifnim - kelifnim" - it is considered as being inside the walls of Jerusalem.
"Min ha'agaf ulachutz - kelachutz" - even though it is still under the doorway, it is considered as having gone outside the boundary, and the sacred food becomes disqualified.
"Hachalonot ve'ovi hachomah - kelifnim" - windows set in the wall, as well as the thickness of the wall itself (such as one standing on top of it), are considered as being within the walls and within the demarcation line, and the offering remains valid.
It is worth noting that although we have spoken of the walls of Jerusalem as the boundary line, this applies to the korban Pesach on the fourteenth of Nissan. On the night of the Seder itself, however, one may not take the korban Pesach outside the house in which it is eaten, and all the laws we mentioned in the mishnah concerning the boundary line - the agaf, the windows and the thickness of the wall - will apply to the house in which the korban Pesach is found on the night of the Seder. If it left there, it would once again require burning.