We now begin the eighth chapter of Maseches Shevi'is. The opening Mishnah of the chapter presents a great general rule that the Sages stated in the laws of Shemittah, and from it we will learn the basic division between food for people, food for animals, and wood.
"Klal gadol amru ba'shevi'is" - a great rule was stated regarding the Sabbatical year:
The Mishnah divides the produce of the Sabbatical year into three categories, each with its own law:
"Kol hameyuchad l'ma'achal adam - ein osin mimenu meluggema l'adam" - anything designated as food for people may not be used to make a poultice or a salve, because items designated for human consumption must specifically be eaten. Because of the sanctity of the Sabbatical year, they may not be used for other purposes.
"V'ein tzarich lomar l'veheimah" - and it goes without saying that one may not make a poultice for an animal from such an item that is fit for human consumption.
"Kol she'eino meyuchad l'ma'achal adam - osin mimenu meluggema l'adam, aval lo l'veheimah" - here making a salve for a person is permitted, but not for an animal.
The third category is "kol she'eino meyuchad lo l'ma'achal adam v'lo l'ma'achal beheimah" - something that has no fixed designation, and for which there is no uniform rule. In such a case, a person has the right to determine its purpose through his intention, and his intention is what determines its law.
"Chishev alav l'ma'achal adam ul'ma'achal beheimah" - if he intended it for human food and for animal food:
If he intended to use it both as food for people and as food for animals - "nosnin alav chumrei adam v'chumrei beheimah" - meaning that we apply to it the stringencies of both categories at once. What are those stringencies?
The stringencies of human food: one may not make a poultice from it, not even for people.
The stringencies of animal food: one may not cook it, since animal food is not normally cooked. This is a stringency that stems from its status as animal food.
"Chishev alav l'eitzim" - if he intended it for wood:
If he decided in his mind to use it only as firewood, and he has no intention whatsoever of using it as food, neither for people nor for animals - "harei hu k'eitzim" - its status is that of wood in every respect. And since wood is not subject to the laws of the Sabbatical year, it does not carry the sanctity of the Sabbatical year.
The Mishnah brings examples of this: "k'gon ha'si'ah v'ha'eizov v'ha'kornis" - three types of plants which, if he intended to use them as wood, are not subject at all to the laws of the Sabbatical year.
In summary: in this Mishnah we learned the great rule of the Sabbatical year: something designated as human food - one may not make a poultice from it, neither for a person nor for an animal; something not designated as human food - one may make a poultice from it for a person but not for an animal; and something designated neither for this nor for that - a person's intention determines its law: if he intended it for both, we apply to it the stringencies of human food (one may not make a poultice from it) and the stringencies of animal food (one may not cook it); and if he intended it for wood, it is considered wood and the laws of the Sabbatical year do not apply to it, as in the case of si'ah, eizov and kornis.