Maaser Sheni, Chapter 1, Mishnah 4. In the previous Mishnah we learned that one who buys an animal with maaser sheni money - a domesticated animal for a sacrifice, or a non-domesticated animal that is unfit for a sacrifice, such as a deer, purchased in order to eat it in Jerusalem - its hide is not caught up in the sanctity of maaser sheni and it reverts to non-sacred status, since the buyer's intention at the moment of purchase was for the meat alone.
Our Mishnah comes to discuss someone who acted improperly, and it lists two cases:
"HaLokeach chayah lezivchei shelamim" - one who buys a non-domesticated animal, which is unfit for a sacrifice, in order to bring it as a shelamim offering. This act accomplishes nothing at all, since a non-domesticated animal cannot be brought as a shelamim.
"Behemah levasar taavah" - one who buys a domesticated animal simply in order to eat it and not in order to bring it as a sacrifice. This act is permitted by the letter of the law, and below we will explain why it is nonetheless problematic.
In both of these cases the Sages ruled that "lo yatza haor lechulin" - the hide is caught up in the sanctity of maaser sheni. And some understand that the Mishnah means this as a penalty, a punishment for someone who acted improperly.
What is the problem with buying an animal for meat to eat?
Buying a deer in order to offer it on the altar as a shelamim is obviously not in accordance with halachah. But what is wrong with buying a domesticated animal - a cow, for example - with maaser sheni money, in order to eat it in Jerusalem and not as a sacrifice? The Yerushalmi explains that by the letter of the law it was permitted to buy an animal fit for a sacrifice not for the purpose of a sacrifice, but rather in order to eat it with one's family in Jerusalem. However, the Sages saw that the people were inclined to refrain from bringing sacrifices on the altar, and therefore they decreed that maaser sheni money may not be used to purchase an animal except for the purpose of a sacrifice; and one who does otherwise was penalized in that the hide does not revert to non-sacred status.
The approach of the Gemara in Menachos:
The Gemara in Menachos explains the Mishnah somewhat differently: it is not that the hide alone fails to revert to non-sacred status, but rather that the entire purchase is ineffective. This is considered like one who bought an animal in order to plow his field, which is not a proper use of maaser sheni money, and therefore the sanctity of maaser sheni does not take hold on the animal at all - and not only on the hide.
Jugs of wine:
This matter is also discussed in the previous Mishnah: one who buys "kadei yayin petuchos" - open jugs of wine, and likewise sealed ones in a place where the practice is to sell them open - "lo yatza kankan lechulin" - the jug does not revert to non-sacred status. The jug is caught up in the sanctity of maaser sheni and must be redeemed. The reason: in both of these cases it is not the practice to sell the wine together with the jug, and once he bought the wine along with the jug, he has explicitly included the jug in the purchase made with maaser sheni money. One cannot say that he intended the wine alone, since he clearly included the jug as well, and therefore the jug does not revert to non-sacred status.
Baskets of olives and baskets of grapes:
The Mishnah concludes with a similar ruling: "Salei zeisim vesalei anavim im hakli - lo yatzu demei hakli lechulin" - baskets of olives and baskets of grapes bought together with the container - the value of the container does not revert to non-sacred status. The value of the container does not revert to non-sacred status but rather becomes sanctified with the sanctity of maaser sheni, because everywhere it is not the practice to include the basket in the sale, and here the buyer explicitly included it, contrary to the accepted practice. This shows that his intention was to buy the container as well with maaser sheni money, and therefore the container is caught up in the sanctity of the money and must be redeemed.
In summary: In this Mishnah we learned that one who buys a non-domesticated animal for a shelamim offering, or a domesticated animal for meat to eat - is penalized, and the hide does not revert to non-sacred status (and according to the Gemara in Menachos the purchase is entirely ineffective); and likewise that one who buys wine in open jugs, or in sealed jugs in a place where the practice is to sell them open, and likewise baskets of olives and grapes together with the container - the jug and the container do not revert to non-sacred status, since he explicitly included them in the purchase made with maaser sheni money, and therefore they are caught up in the sanctity and require redemption.