We are in chapter 2, mishnah 3, continuing with the testimonies of Rabbi Chanina.
A Document Not Written by the Borrower:
Rabbi Chanina would bring two valid witnesses to endorse the document with their signatures and thereby confirm its validity. The question was raised: is this a proper procedure? Why should the borrower not write the document himself? The case came before the Sages - it was brought for a ruling in the Chamber of Hewn Stone, to determine whether this is an acceptable way to draw up documents - and they permitted it. The reason: it is those who sign the document who make it a document, not the handwriting in which it was written.
"Lefi darkecha atah lameid" - Learning Along the Way:
From this approach a further halachah can be derived: "she'ha'ishah kotevet et gitah" - that a woman may write her own get. There are, of course, several halachos governing the writing of a get: the get must belong to the husband, and it must be written in his handwriting or at his explicit instruction. We are therefore dealing with a case in which the piece of paper belongs to the husband, and he explicitly instructs his wife to write the get. The wife serves as the scribe, and once she has written it she hands it to her husband, who then gives it into her hand - for she must receive it into her hand - and the get is valid. At first glance this is counterintuitive, since she is the one writing her own get, but the question of who wrote it does not concern us: the get is nothing more than the instrument by which the husband divorces his wife, and as long as it is a valid get, it makes no difference that she wrote it.
And the reason, in the words of the mishnah, is because the kiyum - the confirmation and validation - of the get. It is worth noting that the word 'get' in this context means any contract or legal document. True, 'get' has come to be reserved for the bill of divorce that a man gives his wife, but in fact it denotes any document, and that is its meaning here. What gives it validity is the very fact that valid witnesses have signed it, confirming that the document is exactly what it presents itself to be. That concludes the first part of the mishnah.
A Needle Found in the Flesh of a Korban:
The second and final part of the mishnah, the last of the four matters to which Chanina, that Kohen Gadol, testified, deals with tumah and taharah. Let us first set out the situation from the outside: a korban has been offered in the Beis HaMikdash, and the kohanim are processing it, flaying it and cutting up the meat. Let us assume for the sake of discussion that it is an olah, which is entirely burned. In the course of the processing the kohanim find a needle stuck in the flesh, and they identify it as a tamei needle. In the specific case of our mishnah, at least according to the Rambam, this is a needle that was inside a corpse and carries tumas meis - the most powerful source of tumah there is. Metal that touches a corpse, such as a needle inside the corpse, becomes an avi avos hatumah just like the corpse itself, and a person who touches it becomes an av hatumah.
Now the questions arise: is the korban tamei? Presumably yes, since the source of tumah is located literally inside the flesh (we will return to this). And what is the status of the knife with which the kohen slaughtered the animal? And what is the status of the kohen himself?
Doubtful Tumah in a Public Domain and in a Private Domain:
The basic content of the mishnah is that we have before us a case of doubt: we do not know what the needle touched. Regarding all those details that we do not know, we rule according to the principle that governs every case of doubtful tumah: a doubtful tumah in a public domain is tahor; a doubtful tumah in a private domain is definitely tamei.
'Public domain' in this context is not the public domain of the laws of Shabbos, which has no partitions and through which people move about, but rather a place in which at least three people are regularly found - a public place, as we learn from the laws of sotah, and not a private one. So too, 'private domain' here is not a place enclosed by four partitions as in the laws of Shabbos, but a place where there are no people present all the time.
The Azarah - the courtyard of the Beis HaMikdash - had people present there constantly, and it is therefore considered a public domain, even though it is surrounded by walls. Accordingly, when we do not know whether tumah was transmitted - and that is our case here, since we do not know for certain whether the kohen or his knife touched that needle - we rule that everything is tahor.
The wording of the Mishnah and its details:
"V'al machat shenimtza b'basar" - a needle identified as a source of tumah that was found in the flesh of an animal brought as a korban.
"Shehasakin v'hayadayim tehoros" - both the knife and the hands of the kohen are tahor.
"V'habasar tamei" - the meat is tamei.
Let us go through this point by point. The knife is tahor, since we do not know that it touched the needle, and this is a case of doubtful tumah in a public domain, where the doubt is resolved as tahor.
As for the hands - there is more here than meets the eye. On the face of it, the general question is whether the kohen is tamei or not. The kohen touched the meat but did not touch the needle, as far as we know, and therefore the ruling is that he is tahor. This requires explanation: after all, we know for certain that the meat itself is tamei, as the Mishnah states. The answer is that those which can receive tumah fall into four categories:
A person - here, the kohen.
Vessels - such as the knife.
Foods - such as the meat of the korban.
Liquids - beverages.
The highest level of tumah that foods can receive is rishon l'tumah, and food never becomes an av hatumah. Therefore, even though the needle is an avi avos hatumah and it is lodged here inside the meat, the carcass is only a rishon and never an av. And since it is a rishon, there is a separate rule: a person or a vessel cannot become tamei from a source that is not an av hatumah. Since food is never an av hatumah, a person can never become tamei from food. It emerges that if the knife or the person touched the meat and not the needle, they are tahor, and the entire question was whether they touched the needle, and out of doubt we ruled that they are tahor.
Why the Mishnah says "hands" and not "the kohen":
The Mishnah does not say that the kohen is tahor but that his hands are tahor, and the reason is this: there is a separate rabbinic law that although items that are a rishon l'tumah do not make a person tamei, they do make his hands tamei. Hands that touch a rishon l'tumah become a sheni l'tumah - the hands alone and not the person's entire body. Even so, this rabbinic law does not apply in the Beis HaMikdash, since the halachah there does not follow it - it would create ongoing tumah problems in the Mikdash, and that is not what we want. This is the Mishnah's intent: even though the kohen's hands certainly touched the meat, and the meat is certainly a rishon, his hands remain tahor, since this is a law unto itself, and this rabbinic law of hands becoming a sheni does not apply in the Mikdash.
How the meat became fit to receive tumah:
The meat is tamei, as stated, since it certainly became tamei. But there is a question here: in order for foods to become tamei, they must first be made susceptible through one of the seven liquids, known by the mnemonic yud-daled, shachak, dam. Now, a live animal that was just slaughtered - where would the liquid come from to make it susceptible? And even if blood splashed onto it, the blood of korbanos does not make food susceptible in any case. The Gemara answers, and Rava cites this, that the animal was dripping with water from the time it entered the Beis HaMikdash: it came in dripping with water because it had passed through water and was still wet, and it is that water which made the meat susceptible to receiving tumah. This is not essential for understanding the Mishnah, but it resolves how the meat became tamei when it requires hechsher.
"V'im nimtza b'feresh - hakol tahor":
If the needle was found in the animal's dung - everything is tahor. And where would it be found? In the intestines, which require cleaning, for one does not offer an olah without first cleaning out the intestines, and the dung is not burned on the altar. If, while cleaning the intestines, that needle which had been lodged in the flesh is found there - it makes no difference, and everything is tahor. The reason: the dung inside the animal's intestines does not belong to any of the four categories - it is not a person and not a vessel, not food and not drink. Even if the animal had diarrhea and everything was liquid, this is not considered a beverage but merely liquid. Dung is not susceptible to tumah, and therefore, even though the needle was inside the animal - and even if the animal itself were physically susceptible to tumah - there is no direct contact between the animal and the source of tumah, and so even the flesh of the animal, the offering, remains tahor.
In summary: In this section we learned the continuation of Chanina's testimonies. A document signed by valid witnesses is valid even though it was not written by the borrower, since it is the signatories who make the document a document, not the handwriting; and from here, incidentally, you learn that a woman may also write her own get, since the validity of every document depends on the witnesses. And regarding the needle found in the flesh of the offering: the knife and the hands are tahor - because of the rule of a doubtful case of tumah in the public domain, and because a person and a vessel do not become tamei from food that is only a rishon, and because the decree of tumas yadayim does not apply in the Temple; the flesh is tamei, once it was made susceptible by the water that dripped from the animal; and if the needle was found in the dung - everything is tahor, since dung is not susceptible to tumah.