1) FRUIT HANGING INTO A HOUSE
QUESTION: Rebbi Yanai maintains that fruit of Tevel becomes subject to the obligation to separate Ma'aser only when it enters one's house. Rebbi Yochanan maintains that entering the Chatzer is sufficient to render it subject to Ma'aser. The Gemara challenges both opinions from the Beraisa mentioned earlier. The Beraisa derives from a verse that a laborer is not required to separate Ma'aser from the fruit that he eats while he works in the field. Since the verse teaches this Halachah specifically with regard to a laborer, it implies that a purchaser who buys the fruit in the field is obligated to separate Ma'aser even though it has not yet entered a house or a Chatzer.
Rav Papa answers that the Beraisa refers specifically to a case in which the fruit tree grows in the garden but its fruit hangs into the Chatzer (according to Rebbi Yochanan) or into the house (according to Rebbi Yanai). Since the fruit is located in the Chatzer or house as soon as it is plucked, the purchaser must separate Ma'aser.
Why is there an obligation to separate Ma'aser from such fruit? Although the fruit is located in a Chatzer or house, it was not brought in through the gate, a necessary condition -- according to both Rebbi Yochanan and Rebbi Yanai -- for the fruit to be subject to Ma'aser. (Rishonim)
(a) The RASHBA cites an opinion (in the name of "Yesh Mi she'Piresh") that in the case of the Beraisa, the trunk of the tree has grown through the gate of the Chatzer, and thus the fruit indeed has entered the Chatzer via the gate.
The Rashba cites the RA'AVAD who rejects this explanation. The Ra'avad contends that even if the tree grows through the gate (and is considered to have entered the Chatzer), the fruit would not be subject to the obligation of Ma'aser because the fruit itself entered the gate before it was picked (before the "Gemar Melachah"). The fruit, therefore, is comparable to wheat that was brought into the Chatzer while still sheathed in its chaff, which is not subject to the obligation of Ma'aser.
(b) The RAMBAN, RASHBA, and RAN answer that the requirement that the fruit be brought through the gate applies only when the fruit grew outside of the Chatzer. Fruit that grew inside of the Chatzer (such as in this case, where the trunk of the tree was leaning into the Chatzer) is not subject to this requirement, and thus the obligation to separate Ma'aser takes effect without the fruit entering the Chatzer through the gate. They add that, on the contrary, this is the most ideal form of "Re'iyas Penei ha'Bayis."
(c) The RITVA writes that when the Gemara says that the trunk of the tree leans into the Chatzer, it means that it is next to the entrance to the Chatzer such that one can pick the fruit from the tree and bring it in without having to leave the Chatzer. Thus, when the fruit is brought into the Chatzer it passes through the gate and becomes subject to the obligation of Ma'aser. (Although this explanation is not given by any of the other Rishonim, the MAHARSHA asserts that this is also the view of TOSFOS, beginning of DH Ad she'Yir'eh.)
2) FRUIT BROUGHT INTO SOMEONE ELSE'S HOUSE
QUESTION: The Gemara teaches that once a laborer brings the fruit which he is allowed to eat into the Chatzer or house of his employer, it becomes subject to the obligation of Ma'aser. The RASHASH questions this from the Mishnah in Ma'aseros (2:2) which teaches (according to the Yerushalmi cited by the RASH there) that when a person brings his fruit into someone else's house the fruit does not become subject to the obligation of Ma'aser. The obligation of Ma'aser takes effect only when he brings the fruit into his own house. Why, then, does the laborer's fruit become subject to the obligation of Ma'aser when he brings the fruit into his employer's house or Chatzer?
(a) The RASHASH gives an answer based on the words of TOSFOS (DH Tevu'as), who says that the laborer does not acquire the fruit until he eats it. Hence, at the time he picks the fruit it still belongs to the employer, and thus the fruit becomes obligated in Ma'aser when the laborer brings it into the employer's house.
(b) The CHAZON ISH (Ma'aseros 3:14) answers that the Rashash's understanding of the Mishnah in Ma'aseros is not accurate. The Rashash understands the Mishnah there based on the Yerushalmi which says that "a Chatzer does not establish [the obligation of Ma'aser] except for the owner." However, the Yerushalmi does not mean that fruit does not become obligated in Ma'aser when it is brought into someone else's Chatzer or house. Rather, the Yerushalmi means that entry into a Chatzer activates the obligation of Ma'aser only for someone who has a regular place ("Kevi'us Makom") in that Chatzer. He does not have to be the owner of the Chatzer, but he must be like an owner who has regular usage of the Chatzer. Therefore, the laborer -- who regularly uses the Chatzer where he eats the fruit that he picked -- becomes obligated to separate Ma'aser when he brings the fruit into the Chatzer of his employer. (I. Alsheich)
3) DERIVING THE PROHIBITION OF "CHASIMAH" THROUGH A "KAL VA'CHOMER"
QUESTION: The Gemara teaches that although the Torah prohibits muzzling an animal and preventing it from eating while it works, the Torah does not prohibit preventing a hired laborer from eating. The Gemara asks that logically the prohibition of muzzling an animal should be extended to a human laborer as well, through a Kal va'Chomer. The owner of an ox has no obligation to ensure that the ox stays alive, but he nevertheless is prohibited from muzzling it. Since a person is obligated to ensure that his fellow man stays alive, a Kal va'Chomer should teach that the prohibition of muzzling certainly applies to an employer who prevents his laborer from eating. The Gemara answers that the verse of "k'Nafshecha" (Devarim 23:25) teaches that just as the employer himself may choose not to eat, he also is not punished if he prevents his laborer from eating.
The Gemara's suggestion that a Kal va'Chomer should teach that the prohibition of "Lo Sachsom" applies to a laborer is difficult to understand. There is a rule that "Ein Mazhirin Min ha'Din" -- a prohibition which is punishable with Malkus cannot be derived through a Kal va'Chomer (Yevamos 22b, Makos 17b).
Although a Kal va'Chomer may serve as a source for a prohibition which does not carry a penalty of Malkus, the Gemara here is not attempting to derive a prohibition for which the employer is not punished with Malkus. The fact that such an Isur exists would be known without a Kal va'Chomer, because the verse itself implies such an Isur. When the verse (Devarim 23:25-26) permits a laborer to eat from the fruit of the field in which he works, it teaches that the owner of the field is obligated to allow the laborer to eat. Since the verse obligates the owner with a Mitzvas Aseh to allow the laborer to eat, he transgresses an Isur Aseh if he prevents the laborer from eating (as the SEFER HA'CHINUCH writes in Mitzvah 576). It is clear that the Gemara seeks to derive through the Kal va'Chomer an Isur that is punishable with Malkus. How can this be reconciled with the rule that "Ein Mazhirin Min ha'Din"? (MISHNEH L'MELECH, Hilchos Ma'achalos Asuros 2:1)
(a) The MISHNEH L'MELECH answers based on the words of the MAGID MISHNEH that in a situation in which an Isur exists even without the Kal va'Chomer, a Kal va'Chomer can be used to teach that there is Malkus, and the principle of "Ein Mazhirin Min ha'Din" does not apply.
(b) The SHA'AR HA'MELECH understands that the Gemara indeed seeks to derive through the Kal va'Chomer only that there is an Isur, but not that the Isur is punishable with Malkus. Although there would be an Isur Aseh even without the Kal va'Chomer (as the Mishneh l'Melech says), nevertheless the Gemara wants to derive that there is also an Isur Lo Ta'aseh (albeit without a punishment of Malkus) against preventing one's laborer from eating the fruits in the field while he works.
(The YOSEF DA'AS asks that if one does not receive Malkus for transgressing this Isur Lo Ta'aseh, then what difference does it make if there is one Isur (an Isur Aseh) or two Isurim? He answers based on the RITVA later (94a) that if there is no Lo Ta'aseh, then when the Torah commands the employer with a Mitzvas Aseh to permit a laborer to eat, it merely establishes the laborer's right to eat. The laborer, however, may forgo his right and accept upon himself not to eat, in which case the employer may prevent him from eating. If, however, the Torah commands the employer with a Lo Ta'aseh to permit the laborer to eat, then the laborer cannot agree to let the employer prevent him from eating.) (I. Alsheich)