Bechoros Chapter 9, Mishnah 3. This is a Mishnah that is quite challenging to read and understand. Therefore, it is best to first explain the concepts orally, and afterward examine its wording as much as possible. But first, a seemingly unrelated topic must be addressed - the matter of the kalbon.
What is the kalbon:
Tractate Shekalim teaches that there is an obligation upon every Jewish male to give a half-shekel annually for the communal offerings in the Temple. The Sages instituted that the one giving the half-shekel must add, under normal circumstances, a small addition called a kalbon - a tiny amount meant to compensate for any loss that might be caused to the Temple treasury due to the coin not being at its full value, such as if it was worn down from use and does not contain the complete silver weight of a half-shekel.
From this emerge two rules:
Two partners giving together: If they do not have exact coins, one of them gives a whole shekel for both of them, and the second repays him his share with any coin. In such a case, each of them must donate his own kalbon, so that the Temple treasury does not suffer a loss.
One giving as charity for his friend: One who gives for another person as an act of charity, and not out of a partnership with him, is not obligated to give a kalbon for him. For example, a father who has two sons who do not have money, and he gives a whole shekel for both of them - he does not give a kalbon at all, since this giving is an act of charity for his sons.
Animal tithe - individual ownership:
Let this matter be set aside to return to the animal tithe. There is a verse from which it is derived that the obligation to tithe the flock applies to an individual owner - "yours," to you as a single person, as opposed to a flock that is jointly owned with another. Therefore, wherever there is a partnership and two people hold a flock together, there is no obligation for an animal tithe. While this means that a person could theoretically bypass the obligation to separate the animal tithe by creating a partnership with his friend, there is not much benefit in doing so. As explained earlier in the chapter, with the animal tithe, a person eats the animal himself, and does not gain or lose too much, aside from the opportunity to bring an offering to God in the Temple. Regardless, the halachah is that an animal tithe is not separated from a flock in a partnership.
The Mishnah teaches that when a father dies and he had flocks, and the sons have not yet divided the estate among themselves - the estate itself, which is the tefisas habayis (undivided household), is still considered as a single private owner over all the assets and over all the flocks. It is as if the deceased father and his estate are the owners. Therefore, the flocks are obligated in the animal tithe, and the sons will divide the inheritance among themselves at a later time.
After the sons each take their share in the flock - suppose there were twenty sheep and each took ten - the estate is divided, that entity no longer exists, and it has no obligation. From now on, an obligation to separate the animal tithe from the flocks he will have in the future will apply to each of them as a private individual. However, as the Mishnah will state, an animal that a person buys or receives as a gift does not enter into the calculation for tithing his flock. For example, if a person had nine sheep and bought a tenth sheep, this does not create an obligation for the animal tithe.
Similarly, the sons who inherited from their father, divided the estate, and took the flocks for themselves - neither of them is obligated to tithe the flock, since they acquired it as recipients. Next year, when new animals are born, each will tithe separately. And if they chose to reunite their flocks, their status is no different from any two unrelated people who decide to enter into a partnership and unite their flocks: even though the flocks originally belonged to a single father and were obligated in the animal tithe, since they were subsequently divided into two separate flocks of two owners, their unification from now on is a unification of partnership - there is no longer an obligation to tithe the united flock.
The rule the Mishnah teaches:
The Mishnah comes to draw a contrast and state that regarding two brothers who inherit from their father: if they are obligated in the kalbon - they are exempt from the animal tithe, and if they are obligated in the animal tithe - they are exempt from the kalbon. And this is how it works:
When a father passes away, he leaves behind an estate. Suppose the sons do not have any money, and the estate contains twenty sheep and one shekel. When the treasurers arrive requesting the half-shekel, the sons say: "We have nothing, but our father's estate, which we have not yet divided, contains a shekel." The estate gives a shekel on behalf of the two sons, and there is no obligation to add a kalbon, since it is considered as if the deceased father is giving on behalf of his children. However, since the estate has not yet been divided, the flocks it owns are considered the property of an individual, and therefore there is an obligation to tithe them. The result is: there is no kalbon, and there is animal tithe.
In contrast, once the brothers have divided their inheritance and each went his own way with his ten animals, and later they decided to form a partnership again - their status is no different from any two people who form a partnership. The flocks are now under joint ownership and not individual ownership, and therefore there is no obligation of animal tithe for them. But if the treasurer arrives in Adar and requests the half-shekel from each, and one brother says to his fellow: "I don't have small change, do me a favor and give a whole shekel and we will settle the account" - they are giving a whole shekel for both of them, and each of them must give a kalbon. It turns out that in the exact same reality where the flock is exempt from animal tithe, they are obligated in a kalbon. This is the central idea of the Mishnah, and although its words are few and their understanding is complex, this is its intention.
Let us look at the wording of the Mishnah:
First the Mishnah says: "Halako'ach veshenitan lo matanah" - an animal that a person buys from his fellow or received from him as a gift, is exempt from animal tithe. It does not enter the tithing calculation and is not placed into the flock with the rest of the animals to be tithed with them, but rather it is separate and set apart on its own.
From here is a new paragraph, and in the Babylonian Talmud it is even considered a new Mishnah, and it has a new topic: the matter of the kalbon and the inheritance. It says: "Ha'achim hashutafin" - brothers who are partners, and this can be in one of two ways: either they have not divided their father's estate and they are equal owners in the undivided estate, or they have already taken their portions and decided to partner together. The Mishnah teaches that the manner in which the partnership was created determines the obligation of the kalbon and the obligation of animal tithe, and that one will always apply and not the other.
"Shechayavin bekalbon" - when they are obligated to give a kalbon, meaning they divided and formed a partnership again, since then their giving is similar to two business partners where one gives a shekel to make it easier for his fellow, and this is not giving in the form of charity, and therefore each of them adds a kalbon to complete his half-shekel. It is a sign that their properties are also in partnership and their flocks are mixed together, and they do not have a single owner - and therefore "peturin mima'asar behemah" - they are exempt from animal tithe.
And on the other hand: "Shechayavin bema'asar behemah" - in a case where the estate is still whole and the brothers have not yet taken their separate portions, the estate is considered the single owner of the flocks and there is an obligation to separate animal tithe. But then "peturin min hakalbon" - they are exempt from the kalbon, since once the estate pays the shekel for the two sons, it is like a father or an estate paying for his sons, and they are like receivers of charity, and there is no obligation to add a kalbon.
Now the Mishnah demonstrates the matter, and here its precise reading becomes very complex. It says: "Kanu mitefisat habayit" - this is how the word "kanu" and the letter "mem" after it should be understood, and so the Bartenura explained: the intention is that the sons inherit from the undivided estate, meaning their father died and he had flocks, and they are the heirs and owners of those flocks by inheritance, but they have not yet divided the estate. Since there is still a single owner here - "chayavin" - they are obligated in animal tithe. "Ve'im lav peturin" - and if they have already divided the estate between the two of them and each went his own way, ten sheep for each out of the twenty in the flock, they are exempt from animal tithe.
"Chalku vechazru venishtatfu" - they divided the flock and each took his ten sheep, and later they decided to return and be partners in all their affairs. In this case "chayavin bekalbon" - when they give one whole shekel for both of them, they are financial partners sharing their obligations and this is not a donation, and therefore each of them adds a kalbon. "Ufturin mima'asar behemah" - since this is a flock under joint ownership, and it is exempt from the obligation of animal tithe.
The source of the law:
The foundation of the technical exemption, that a flock that is not under private ownership is not obligated in the separation of animal tithe, is the verse in the Book of Exodus chapter 13: "Vechol peter sheger behemah asher yihyeh lecha" - "yihyeh lecha" (that you will have) means that it will be yours, in the singular form. And even though the context of the verse deals with firstborn animals, we learn from it for animal tithe. These are technical matters, but this is the law, and with God's help the concepts are clear.