Bava Metzia, Chapter 8, Mishnah 8. The Mishnah continues to discuss the halachic matters between a landlord and a tenant, and here it deals with the question of the extra month in a leap year: in the Jewish calendar, an extra month is added in a leap year, resulting in thirteen months instead of twelve. The question is how this addition affects the rent.
It is appropriate to preface that this halachah was stated at a time when the establishment of a leap year was entrusted to the Beis Din and was not known in advance: the decision whether the year would have twelve or thirteen months was made at the end of the winter, and until then the matter was in doubt. Today, since the permanent calendar has been established - with seven leap years in every nineteen-year cycle - a leap year is completely predictable.
The Two Methods of Renting:
"Hamaskir bayis lachaveiro leshanah, nisabrah hashanah - nisabrah lasocher" - the profit belongs to the tenant. This refers to a case where the landlord said, "I am renting the apartment to you for this specific year," and once the rental is set for the calendar year, the tenant acquires that entire year, whether it has twelve months or thirteen. If it became a leap year - he essentially receives one month for free.
"Hiskiru lachodashim, nisabrah hashanah - nisabrah lamaskir" - the profit belongs to the landlord. If the rental was set by the month, the tenant pays full rent for the extra month as well, since the calculation is monthly and does not depend on the number of months in that year.
An Incident in Tzippori:
The Mishnah brings an incident where the contract included both expressions simultaneously: "Maaseh b'Tzippori b'echad shesachar merchatz meichaveiro bishneim asar zahav leshanah, vedinar zahav lachodesh" - a person rented a bathhouse, and the contract stipulated that his rent would be twelve gold coins per year, one gold coin per month.
The first half of the sentence sounds like an annual rental - twelve gold coins, whether the year has twelve months or thirteen; while its second half sounds like a monthly rental, meaning that in a leap year it would be thirteen coins. From here arises a doubt that spans the entire Torah: when a contract or statement is composed of two parts, and the first part contradicts the second - do we follow the first part or the last part?
"Uva maaseh lifnei Rabban Shimon ben Gamliel velifnei Rabbi Yosi, ve'amru: Yachaloku es chodesh ha'ibur" - the question regarding the bathhouse in Tzippori was brought before these two great sages of the world, and they ruled to divide the extra month: half a gold dinar rent for that month.
This ruling is based on the opinion of Sumchos, which has already been mentioned many times in this chapter: "Money in doubt is divided." When it is not known to whom the money belongs, it is divided between the two litigants, the claimant and the defendant, half and half.
The Practical Halachah - The Burden of Proof is on the Claimant:
The halachah does not follow Sumchos, but rather the Sages, that the burden of proof is on the claimant: one who comes to extract money from the person in possession of it - the burden is upon him to bring proof.
And here the matter is fascinating. Usually, the rule is understood simply - one who comes to extract money from his fellow must bring proof in order to do so. But in our case, what is the practical ruling? The tenant is obligated to pay the full rent to the landlord. And this seems difficult: after all, neither of the parties can bring proof as to the interpretation of the contract, so why do we not say that the tenant is exempt from paying, since it seems as if the landlord is the one extracting money from the tenant's pocket?
The answer is that the meaning of the rule is that Beis Din does not uproot the existing status - the chazakah - without proof. As we learned in Mishnah 4 regarding the cow that gave birth, when it is unknown whether she gave birth before the acquisition or after it: if the calf is found in the courtyard of one of them, it remains in his possession; but if it is found in an ownerless place, we establish it on the chazakah - the mara kama, the original owner of that cow.
So too here. The dispute is not over the payment of rent itself, but over the rights: the landlord claims, "This is my apartment, and if you wish to remain here - you must pay," and the tenant claims, "I have the right to dwell here, as I rented it for a year." And who is the muchzak? With land, there is no physical grasping, and there is nothing that can actually be held. (And in the coming chapters, in Bava Basra, we will delve deeper into the question of being a muchzak regarding land, which a person cannot grasp with his hands at all.)
Therefore, we return to the mara kama, the original owner - and this is the chazakah. In this case, the chazakah belongs to the owner of the apartment, as the apartment is his with certainty and without any doubt. And since the tenant cannot bring proof, he has no claim to dwell there without payment: he remains in the apartment, but he must pay rent for that additional month as well - and this is the practical halachah.
In summary: In this Mishnah we learned that a rental set for a year - the leap month is included in the rental and the benefit goes to the tenant; whereas a rental set by months - the benefit goes to the landlord. In the incident in Tzippori, where both expressions were included together in the contract, Rabban Shimon ben Gamliel and Rabbi Yosi ruled to divide the leap month, following the view of Sumchos that "money placed in doubt is divided." But for the practical halachah, we follow the Sages, that the burden of proof rests on the one seeking to extract money from his fellow, and we establish the matter on the chazakah and on the mara kama - and therefore the tenant must pay full rent for the additional month as well.