We continue with Maseches Pe'ah, chapter 5, mishnah 5. The mishnah addresses the question of who is considered the owner of the produce with regard to the gifts to the poor and with regard to Terumah and ma'asros, and it presents four cases.
"HaMachlif im ha'aniyim" - one who exchanges with the poor:
This is a person who exchanges his own produce for the produce of the poor. The underlying principle is that exemption and obligation are not determined by the identity of whoever is holding the produce, but by the identity of the produce itself:
"Shelo patur" - his own is exempt: Leket, shichechah, pe'ah and ma'aser ani are not obligated in Terumah and ma'asros. Once the poor man's produce passes into the hands of the wealthy householder, it remains exempt, and it makes no difference that the one holding it is wealthy, since the exemption is determined by the nature of the produce, namely that it is produce of the gifts to the poor.
"Shel aniyim chayav" - that of the poor is obligated: The produce the poor received, since it came from the hands of the wealthy man, is obligated in Terumah and ma'asros.
The commentators explain that the mishnah means that the obligation rests upon the wealthy man to separate the Terumah and ma'asros before he gives his produce to the poor man.
Two who took a field as sharecroppers:
Two poor men who undertook to be sharecroppers in a single field. Each of them is considered the owner of his own portion, and the crop that comes out of his portion is called his "ketzircha" (your harvest), and therefore he may not take the ma'aser ani that comes from his own portion. In his fellow's portion, however, he has no ownership at all, and ma'aser ani coming from there is permitted to him. Therefore we learned: "Zeh nosein lazeh chelko ma'aser ani, v'zeh nosein lazeh chelko ma'aser ani" - this one gives the other his portion of ma'aser ani, and this one gives the other his portion of ma'aser ani.
One who takes a field to harvest:
A poor man who undertook to harvest another person's field is "asur b'leket shichechah u'fe'ah u'ma'aser ani" - forbidden to take leket, shichechah, pe'ah and ma'aser ani. Since he is the one performing the harvesting, the harvest is considered his own harvest, and the verse "leket ketzircha lo t'lakeit" (you shall not gather the gleanings of your harvest) applies to him, meaning that a person does not take the leket from his own harvest, and the same law applies to the rest of the gifts to the poor in that field.
Rabbi Yehudah's qualification:
Rabbi Yehudah qualifies the law and says: "Eimasai? Bizman shekibel mimenu l'mechetzah, lishlish v'lirvia" - when does this apply? When he took the field from him for a half, a third or a quarter. That is, when his wages are a percentage of the crop he harvests, a half, a third or a quarter. In such a case the harvesting is considered literally his own harvest, and therefore he is forbidden to take any of the gifts to the poor.
But if the owner of the field said to him, "Shlish mah she'atah kotzeir shelach" - a third of what you harvest is yours, meaning that only after you harvest will I give you a third as your wages, after the fact and not from the outset, then he is "mutar b'leket shichechah u'fe'ah, v'asur b'ma'aser ani" - permitted in leket, shichechah and pe'ah, but forbidden in ma'aser ani. The distinction depends on the moment at which the obligation takes effect:
Leket, shichechah and pe'ah: Their obligation takes effect at the time of the harvesting, and at that moment he did not yet have any share whatsoever in the produce, since he only acquires his wages afterward. Therefore he is permitted to take them.
Ma'aser ani: Its obligation takes effect not at the time of the harvesting but after the produce has already been harvested, and at that moment he already has a share in the crop. And since part of the crop belongs to him, he may not take ma'aser ani from it at all.
In summary: In this mishnah we learned four cases: one who exchanges with the poor, where exemption and obligation follow the identity of the produce and not the identity of the one holding it, and the wealthy man must separate before giving; two sharecroppers in a single field, where each is forbidden to take ma'aser ani from his own portion and permitted in his fellow's portion; one who takes a field to harvest, who is forbidden in all the gifts to the poor, since the harvesting is called his own harvest; and Rabbi Yehudah's qualification, which distinguishes between one who takes his wages from the crop itself and one who takes his wages after the harvesting, in which case he is permitted in leket, shichechah and pe'ah and forbidden in ma'aser ani, all according to the moment at which the obligation takes effect.