The Mishnah discusses the permissibility of conducting business with idolaters. If one encounters idolaters on their way to a house of idolatry, it is forbidden to do business with them. The reasoning is that any profit they make might immediately be attributed to their idol worship, leading them to thank their deities. However, if they are encountered on their way back from a house of idolatry, it is permissible to engage in business. In this case, "what was, was" – the act of worship is concluded, and they are not expected to return to offer thanks for new profits.
Shmuel elaborates on this, distinguishing between a general idolater and a Jew who has become an idol worshipper. For a regular idolater, the rule stands: forbidden on the way there, permissible on the way back. However, for a Jew who has become an idol worshipper, the ruling is reversed in one aspect. If such a Jew is encountered on the way to a house of idolatry, it is permissible to do business with him. This is because there is a chance he might change his mind and perform repentance before reaching the idolatrous site. But if he is encountered on the way back, it is forbidden. The logic here is that once a Jew has engaged in idol worship, he becomes "attached" to it, and there's a concern he might reverse course and return to thank the idols for any new business. This implies that a Jew who has strayed into idolatry can sometimes be more zealous than a born idolater.
Abaye further explains this reasoning: for a Jew who has sinned and worshipped idols, this is a new lifestyle. He becomes deeply attached to it, even more so than a typical idolater, and thus might return to the house of idolatry even after leaving. The Gemara then presents a challenge from a different teaching which states that for a Jew going to a house of idolatry, it is forbidden whether on the way there or on the way back. This apparent contradiction is resolved by clarifying that this latter teaching refers to a Jew who is already an apostate, a confirmed rebel in idolatry. Such an individual is not expected to turn back or repent, so doing business with him is forbidden at all times related to his idolatrous journey.
The discussion then shifts to a different scenario: an idolater going to a market where items for idol worship are sold. In this case, it is permissible to do business with him, whether he is on his way to the market or returning from it. The initial question arises as to why this differs from the previous case, especially for someone returning from such a market, as one might suspect he sold idols there. Yom Kippur explains that an idolater typically attends their general market for various transactions, selling regular goods like clothes or a donkey, not necessarily idols. Therefore, the money he carries is presumed to be from permissible sources.
However, the case of a Jew going to such a market is different. If a Jew is on his way to an idolater's market, it is permissible to do business with him. But if he is on his way back, it is forbidden. The reasoning is that a Jew would only go to an idolater's market if he had specific items for them, namely idols, to sell. The Ritbah adds a business perspective: an idolater finds it profitable to sell general goods in their own market. A Jew, however, would not typically frequent an idolater's market for general commerce, nor would he be interested in merely observing idolatry. Therefore, if a Jew is present there, it is highly probable he is selling forbidden items, and any money he possesses would be proceeds from idolatry, which are forbidden to benefit from. This distinction highlights that while the idolater is a general businessman, the Jew in this context is assumed to be dealing in contraband related to idolatry.
Returning to the initial discussion about idolaters coming from a house of idolatry, the Gemara states that it is permissible to do business with them on their way back, but this applies specifically if they are returning individually. If they are returning in groups, it is forbidden. The logic is that when in a group, peer pressure might lead them to return to the house of idolatry to offer thanks for any new business. Their continued presence in the group suggests a collective plan, rather than simply heading home.
The discourse then transitions to the koshering of vessels. It is forbidden to place Jewish wine into leather jugs or earthenware jugs that have previously contained the wine of idolaters, because the idolater's wine is absorbed into the vessel. This absorbed wine, known as forbidden wine, would render the Jewish wine forbidden. Yom Kippur provides specific rules for leather jugs. New leather jugs that are untarred are permissible. However, old leather jugs, or new ones that are tarred, are forbidden. Old jugs are problematic because wine would have been absorbed over a long period. Tarred jugs are problematic because the tar immediately absorbs the wine. Thus, only new, untarred leather jugs are permissible without further processing. This distinction is crucial for leather jugs, as earthenware jugs are considered to absorb immediately, regardless of age or tarring.
Regarding the process of tarring vessels, if an idolater is tarring a vessel and a Jew watches him pour wine into the tar as part of the process, it is permissible. This raises a question: why is it permissible if the idolater is adding wine? The explanation is that the Jew is actually adding his own wine, and the role of the watching Jew is to ensure that the idolater, who is also involved in the vessel's preparation, does not surreptitiously add any forbidden wine. The Jew is preoccupied with his own task, and the presence of another Jew is to supervise the idolater.
Rav Zvid offers a different understanding. He posits that even if the idolater adds wine to the tar during the tarring process, it is permissible. His reasoning is that the wine, at this stage, acts as an ingredient in the tar. Once the tar dries, no remnants or taste of the wine remain; it becomes fully integrated into the tar, similar to how water disappears into tar. Therefore, there is no issue of forbidden wine. If this is the case, then why is supervision needed? Rav Zvid explains that the supervision is not for the initial pouring of wine into the tar, which is inherently permissible, but rather for *after* the tar dries. The concern is that the idolater might then add more wine to the tarred vessel, which would be absorbed and render the vessel forbidden.
Rav Papi attempts to derive a broader principle from Rav Zvid's view: if one pours wine into salt, it should also be permissible, as the wine would be lost and untraceable within the salt. However, this analogy is rejected. The distinction is that when wine is added to tar, it loses its identity and taste. But when wine is added to salt, the wine's taste remains and affects the salt, even after drying. Therefore, salt is not analogous to tar in this context.
The Gemara recounts a story involving Bar Adi Tayya'a, an Arab merchant, who stole leather jugs from a rabbi, filled them with wine, and then returned them. The question arose as to how to kosher these jugs. The recommended method is to fill the jug with water, leave it for 24 hours, empty it, and repeat this process three times. This procedure is believed to extract the absorbed wine. A query was raised whether this method applies only to Jewish vessels that were subsequently used by idolaters, or also to vessels that were originally made and used by idolaters. The conclusion is that this form of purification works for both, regardless of the vessel's origin. The 24-hour soaking period is essential for the water to effectively draw out the absorbed wine.
Rabbi Yochanan held that this koshering method is effective only for leather jugs, which do not absorb as much. He believed it would not work for earthenware jugs, which absorb significantly more. However, Rabbah disagreed, asserting that this method is effective for both leather and earthenware jugs. The Gemara then provides another ruling regarding earthenware jugs: new, untarred ones are permissible, as any wine stains would be visible. However, old earthenware jugs, or any that are tarred, are forbidden. Old jugs would have absorbed wine over time, and tarred jugs would absorb wine, with the tar concealing any visual evidence.
For old or tarred earthenware jugs, there are two primary methods of koshering. One is the three-day water purification, where the vessel is filled with water for 24 hours, emptied, and refilled, repeating this for three consecutive days. The second method involves using fish brine or fish innards. This powerful substance is believed to "burn out" the absorbed wine. There is a difference of opinion regarding how long the fish brine needs to remain in the vessel, with some suggesting a short period, others 24 hours, and some even three days. A question then arises whether using fish brine is an ideal initial method or only permissible after the fact. The answer clarifies that it is permissible initially, and one may even consume the fish brine afterwards, as it does not become forbidden. New earthenware jugs, however, require no such koshering; one may simply put their own wine into them, while old ones do require purification.
The Gemara then considers whether re-firing an old, wine-absorbed vessel in a kiln would kosher it. The answer is affirmative, reasoning that if fish brine can burn out the wine, then fire, which is far more potent, would certainly achieve purification. This process is akin to intense heating. A potential concern is raised: perhaps we cannot trust someone to perform proper intense heating, as they might fear the vessel will crack and thus remove it from the fire too soon. The response is that such a concern is unwarranted because these are inexpensive vessels, and the person would not be overly worried about them breaking. Alternatively, if even fish brine can do the job, then even a moderate amount of fire would suffice, thus alleviating the concern about insufficient heating.
Rabbi Yochanan, in the name of Rabbi Bah, states that earthenware jugs that are tarred become permissible if they are fired until the tar melts. Rabbah clarifies that it is not necessary for the tar to completely slide off the vessel; it is sufficient for it to soften due to the heat. Another method of purification involves inserting kindling or wood chips inside the vessel and burning it from within. One opinion deems this forbidden, arguing that internal heating provides less heat than an external kiln and thus does not thoroughly purify the vessel. Another opinion permits it, asserting that it is no less effective than fish brine. Ashi offers a fundamental distinction: heating from the outside in a kiln thoroughly heats the vessel until the tar becomes like a hot brick. Internal heating, however, only melts the tar immediately from within without bringing the entire vessel to a sufficiently high temperature.
Therefore, for barrels that have held wine for a long time, internal purification methods, whether fire from kindling or even boiling water, are insufficient. Such barrels require either external heating in a kiln or the three-day water purification method. Another option for these barrels is to leave them unused for twelve months. After this period, the absorbed wine becomes spoiled and degraded, rendering the barrel permissible for use. This means that for deeply absorbed wine in large barrels, internal heating or simple boiling water from the inside is not enough; the purification must be thorough, either through external fire, prolonged water soaking, or the passage of a significant amount of time.
Finally, the Gemara discusses putting beer into wine casks. One rabbi states it is forbidden, as the absorbed wine would leach into the beer, making the beer forbidden. Another rabbi holds it permissible, arguing that the beer itself would nullify or destroy the taste of the wine. The general rule usually requires sixty parts of a permissible substance to nullify one part of a forbidden substance. Here, the concern is that the walls of the vessel might not have sixty parts against the absorbed wine. However, one explanation suggests that the moment the wine leaches from the vessel into the beer, it immediately becomes spoiled, thus nullifying itself. This explanation is countered by noting that this immediate nullification typically applies when substances are boiling. In a cold environment, not everything from the walls would leach out, and thus the sixty-to-one ratio might still apply, making it permissible.
A story is related where someone was instructed to put beer into clay casks but mistakenly put wine instead. The ruling was that this was permissible. The reason is that such an error, a simple mistake, does not necessitate rescinding the permission for beer. We do not suspect that allowing beer will lead people to mistakenly put wine into such vessels as a regular occurrence. It was a specific error, and wine mixed with wine does not become spoiled; it simply remains wine.