Eruvin 53 – Long short road

The residence area for Shabbat (techum) extends two thousands steps from the border of the city. What is considered border for this purpose? If the corner houses are not in a straight line, they measure the techum from those houses that are farther away from the center. Any additional ruins, bridges or tombs also extend the techum.

The word “extends” can be spelled with an aleph (מאברין), meaning “a limb,” or with an ayin (מעברין), meaning “pregnant”. Rav holds one view on this, while Shmuel – the other. The Talmud lists other differences between Rav and Shmuel: (a) was the “new king of Egypt” really new, or did he just take new measures to oppress the Jews; (b) was the grave of the patriarchs called “double” (machpelah) because it had two stories or because it had multiple couples buried there, and (c) was Nimrod the real name of the king and was he called Amraphel (which means “said and threw”) because he commanded to throw Abraham into the fire, or was his real name Amraphel, and he was called Nimrod (rebel) because he caused people to rebel against God.

The Talmud then finds multiple examples where using precise language is very important, and ends up with the story of Rabbi Yehoshua, who asked a boy sitting at a crossroad, “Which is a good road to town?” The boy said that one road was short but long, and the other – long but short. Rabbi Yehoshua chose the short road, but near the town he was met with gardens and fences, which made it very hard to pass. He came back and asked the boy about his advice. The boy said, “Didn't I tell you, it was short but long?” Rabbi Yehoshua then chose the long but short road and eventually got there.

Art: Koloman Moser - Blooming Flowers with Garden Fence

Eruvin 52 – His friend turned him back

If one set out on a Friday afternoon, to go to a nearby city and make his Shabbat residence over there – but his friend convinced him not to go, saying that it was either too hot or too cold, and he returned back home – nevertheless, he is allowed to go the city of his destination, but all other residents of his city are prohibited from going there.

Why? What is the difference between him and his neighbors? They did not reach the other city to establish the residence over there – but he did not either! Rav Huna explained. We are talking about someone who has houses in both cities, so potentially he can decide to reside in this other city ofnShabbat. So, when he started on the road, without food, he has the status of a poor. Therefore, his verbal declaration of residence in sufficient - this is a leniency reserved only for the poor, and actual going there is not required. However, his neighbors who stayed at home, they do have bread at home, and are considered rich. And rich people are not allowed to designate their residence by verbal declaration alone, they need to put bread in this new place. This is why he is the only person who is allowed to go there.

Art: Thomas Keyse Gloucester - A still life with bread, cheese, a pie

Eruvin 51 – Is the residence area (techum) round or square?

Rabbah and Rav Yosef were traveling on the road late Friday afternoon, and they were concerned about their residence area for Shabbat. Rabbah said to Rav Yosef, “Let our Shabbat residence be established under that tree (he knew it) that produces so much fruit that it relieves its owner of paying taxes.” Rav Yosef countered, “But I don't know it.” Rabbah then quoted in the name of Rabbi Yose, “One who does not know the place can rely on the other one who does.” That was not actually true, the rule was not in the name of Rabbi Yose, but Rabbah attributed it to him on purpose, so that Rav Yosef (who was blind) would accept its authority, since Rabbi Yose is known for deep reasoning behind his rulings.

What is the source for the two thousand steps limitations? It comes through a chain of “same word” connections, which ends up with the city of Levites, having a two thousand amot area of space and vineyards around it.

Was the techum area square or round? Rabbi Chanina ben Antignos says that it was round. What about the cities of the Levites, whose area around was square? – He notes that the Torah says “This will be or them the area around,” and explains, “This for them” but not this for others. And the other teacher? He understands it, “Like this, for them and for others.”

Art: Gustave Courbet - Red Apples at the Foot of a Tree

Eruvin 50 – It got dark while on the road

If one was walking on Friday afternoon, and he saw that it was getting dark fast, too fast for him to reach his home – but he noticed a tree that he knew was two thousand steps away from his home – then he should designate his residence under that tree. He would be able to walk to the tree, and then two thousand steps to his home.

However, he should express it correctly. If he just says, “Let my residence be under that tree,” - he has not said anything. He should have designated the specific four steps, such as “next to the trunk.”

What does it mean, “He has not said anything?” Rav says, literally, he got nothing: he lost his current area, did not acquire a new one, and has to stay within four steps of the place where the sundown catches him. However, Shmuel says that he acquired his residence somewhere, only it is not known where. Therefore, he can walk to the tree, if it is close enough, but he may not walk to his home – if it is exactly two thousand steps from the tree. That is because his residential four steps may be behind the trunk, away from home, and thus farther away than two thousand steps from his home.

They asked question on Rav, based on an old ruling (Mishnah) as follows: “If one asked his servants to prepare him an eruv with bread, and they did it in two places, then he can only walk in the common area of the two.” However, he can surely move for more than for steps! And they answered that Rav lived for 300 years, both in the time of the Mishna and of the Talmud, and was thus the only Talmud Sage whose opinion was part of the Mishna; thus, this contradiction did not present a problem for him.

Art: Paul Cezanne - Village behind Trees, Ile de France

Eruvin 49 – How does the eruv really work?

If people from different houses share a common courtyard, this is similar to a street, so the Sages prohibited them to carry in the courtyard on Shabbat – unless they put some common food (eruv) in one of the houses, each one contributing his portion.

How does this device work? Shmuel says that everybody acquires a portion in this house where the eruv is stored. The courtyard then belongs to this one house, is a single area, and they can all carry there. We can ask Shmuel that if so, why do they need bread at all? Let them use the money! Shmuel will answer that money is not always available on Friday afternoon, but bread is.

However, Rabbah says that the eruv works because where your food is – that's where you live, and in effect, everybody temporarily moves into the house with the eruv. What difference does it make, and why do we need different explanations?

The first difference is when they made the eruv with baskets, not bread. It works according to Shmuel, because they acquire a portion in the house, but not according to Rabbah because a person does not live where his basket is.

The second difference manifests itself if they all put together pieces of bread, each worth less than a small coin, prutah. Now it will not work according to Shmuel, because a value less than a small coin can not acquire anything. However, one can establish his residence even with a small piece of bread, and so this justifies Rabbah.

Finally, the third difference is when they ask a minor to collect bread from everybody. Again, it does not work according to Shmuel, because a minor cannot be an agent to acquire things, but he can perfectly well carry bread to a house and deposit it there, just as Rabbah said.

Art: Pieter De Hooch - The Courtyard of a House in Delft

Eruvin 48 – Objects brought to market by non-Jews

We know that objects belonging to a Jew have the same limitations on travel as their owner. On Shabbat, one cannot carry at all. But on a Festival, they can be taken only as far as the owner himself can go, two thousand steps from his residence. By contrast, ownerless objects acquire residence on their own, same say, just four steps around them, and others – two thousand steps.

What about objects (say, sheep) that were brought to a market by a non-Jews from a distance greater than two thousands steps? Some say that they are like ownerless objects, and a Jew may buy and use them on a Festival (of course, not by paying money, but but promising to pay later). Others say that they have the same law as Jewish objects – for without this law the Jews also may eventually forget the techum limitations.

Such case actually happened, and Rava allowed everyone to buy them, following the first opinion. When he heard that Rabbi Yochanan upholds the second view, he reconsidered and said that the sheep can only be moved four steps around their residential area. However, since their new residential area was that town where the fair happened to be, all residents who live there could actually buy and use the sheep for the Festival, but not anyone out-of-town.

Art: Bela Pallik - Sheep

Eruvin 47 – Who does the law follow?

The majority of the laws are formulated by the four students of Rabbi Akiva: Rabbi Yose, Rabbi Yehudah, Rabbi Meir, and Rabbi Shimon. Whenever they disagree, the law is decided first in accordance with Rabbi Yose, if he is one of the disputants, then Rabbi Yehudah, and so on, in the order listed above.

However, Rav Mesharshya said that these rules are not true. That is strange: these rules are so well established that hardly anybody argues with them. The Talmud goes through multiple example, trying to agree with Rav Mesharshya. For example, to change one's residence area for Shabbat (techum), a poor man can walk to the new place on Friday evening and stay their until night, and a rich man can put his food there, even through a messenger. Rabbi Meir says that these laws are for the benefits of the poor, who alone is allowed to do in the first one, but Rabbi Yehudah says that they are a leniency for the rich. On that, Rav said “The law follows Rabbi Yehudah.”

But Rav did not have to say this! We know it from the rules of precedence! It must be, therefore, that Rav Mesharshya is right, and the rules of precedence do not apply!? – No, only Rav does not agree with them, but others do.

The Talmud then makes a few more attempts, but concludes that everybody agrees to the rules of precedence and Rav Mesharshya must be wrong. Then what did he mean by his statement? – Only that these are not universally accepted, and there is at least one Sages who disagrees – this Sage being Rav himself.

Art: Giovan Francesco Locatelli - The rich and poor

Eruvin 46 – Residence area for rain water

Earlier we saw that not only humans but inanimate objects too have their designated area (techum), so that they cannot be moved beyond the two thousand steps. On Shabbat one cannot carry things in the street anyway, but on a Yom Tov (Festival) this law would apply. Someone's objects would have the same restriction as their owner. By contrast, ownerless objects have no owner. Some say that they do not acquire any techum, and thus cannot be moved beyond four steps, others – that they acquire the two thousand steps around them.

What about rain water? We have a rule that whoever picks up rainwater collected on a Festival can carry it as far as he can go. Why is that? The rainwater should acquire residence in the ocean or in the cloud!? And if you try to answer that the water is not physically present, that it is vapor, then I will say that it's even worse – if it only appears on a Yom Tom, then it is something new that came into existence just now, and the rule is that one should not use it at all! Rather, our explanation should be that the water in the cloud is constantly moving. As such, it does not acquire any techum whatsoever, and when someone picks it up, the rainwater gets its new owner's techum. The same explanation would work even if we say that the water evaporated from an ocean just today – it was moving there also, and never acquired the techum restrictions.

Art: Joseph Henderson - Summer Clouds

Eruvin 45 – Residence area of a traveler

As we will learn later, a traveler can mentally designate his residence area for Shabbat, or techum, even if he will reach it only on Shabbat. What if he sat down to rest while he still was on the road on Friday afternoon, and once he arose after dark, he saw that there was a city nearby where presumably he would like to be on Shabbat? Rabbi Meir says that intentional designation of a techum is required. Since our traveler did not do so, he cannot enter the city. However, Rabbi Yehudah says that since his presumed intention would be to enter the city, we count it as a real intention, and he may enter – and travel two thousand steps around it.

What if the traveler fell asleep on the road, while Shabbat was approaching? Rabbi Yochanan ben Nuri says that he nevertheless acquired a techum around himself, for the two thousand steps – but the Sages says that he can only move four steps about. What is the argument? One explanation is that a sleeping person is treated like an inanimate object, and they really argue about inanimate objects – do they also acquire a techum or no.

If two people are stuck on Shabbat, and each has only four steps to move about him, but their techum's overlap – they can bring food and eat together, provided that one does not take food into his four steps area and away from his friend's area. This presumes that food acquires the techum of the owner, however small.

Art: Italian School - A sleeping man

Eruvin 44 – Human fence

Nechemyah, the son of Rabbi Chanilai, became so engrossed in the contemplation of his learning that he walked out of his residence area (techum). Now all he could walk was four steps around him, and he was not permitted to go back to his town or to his home. When Rav Chisda heard of this, he was talking to Rav Nachman, and said, “Nechemyah, your student, is in suffering.” Rav Nachman replied, “Make a human fence – that is, line up people to create a corridor, and he will be able to enter back into his techum through it.

Rav Chisda did so, and Nechemyah came back. But how were they allowed to create a human fence? After all, they are creating a partition and a private area on Shabbat!? – Rav Chisda called them, but he did not tell them why he called them, so they were not consciously doing it. But how were they allowed to walk beyond the techum? – They all have made an eruv in a different place, so they were allowed to walk farther than Nechemya. But still, people might misunderstand this law and do it voluntarily next time? – That is true, and such a ruse is only allowed for a scholar like Nechemyah.

To illustrate, later there was a story when Rava was returning from a lecture he had delivered on Shabbat, surrounded by throngs of people, and his attendant used this live partition to bring back some flasks that were left in the public square. However, when on the next Shabbat the attendant wanted to do the same, Rava forbade it, because now people were aware that they were used as a human partition.

Art: Adriaen Frans Boudewijns - A Crowded Village Scene

Eruvin 43 – How high is the techum?

The private area extends above until heaven and below as far as it can go; if one transfers from a public area to it – he is liable. However, public area goes only as high as ten hand-breadths, and higher than this its limitations do not apply. Of course, if one sits on a high pole in a street, he is nevertheless considered to be in the public area, since the pole rests on the ground. However, if one flies in the air, using one of the mystical names of God, do the limitations of techum apply to him? Can he fly beyond two thousand steps? The same question would apply for a ship that is flowing more than ten hand-breadths above the sea floor.

Can we derive the answer from the story of the ship in the sea, where the limitations of techum seemed to apply? – No, because perhaps that ship was in shallow waters. Another story: once seven rulings about terefah were told to Rav Chisda on Shabbat morning in the city of Sura, and on Shabbat afternoon to Rava in the city of Pumbedita. The distance between those two cities is certainly more than two thousand steps, and who could have recited the ruling but Elijah the Prophet, who travels with the help of the names of God!? It must be then that the techum does not extend above ten hand-breadths from the ground! – No, the ruling could have been brought by the well-known demon by the name of Yosef, who does not observe the Shabbat laws anyway, so we cannot learn anything from his behavior.

Art: Viktor Vasnetsov - Flying Carpet

Eruvin 42 – Shabbat on a ship

If gentiles took him away from his residence area (techum) on Shabbat and brought him into a fold or corral, can he walk the complete area of the corral? Rabban Gamliel and Rabbi Elazar say that, since it is a private area, he can freely walk there. However, Rabbi Yehoshua and Rabbi Akiva contend that because he lost his techum, he can walk only four steps around, and that's it.

It once happened that these same four people were on a ship. When Shabbat started, they were in a port, but later the ship moved out to sea, and they lost their original techum. Following their respective opinions, the first pair moved freely around the ship, but the second one only walked for four steps around.

However, upon closer examination, even they could walk the complete ship – is' just that they chose to follow this additional stringency, in order not to mislead the people who would not know the difference between placed in a corral and on a ship. And what is indeed the difference? With the corral, one did not acquire residency there before Shabbat, but instead was brought there. However, with the ship, one acquires his residency there at the beginning of Shabbat. Others say that since the ship keeps moving, he is always walking only four steps – except these four steps keep changing as the ship moves. Why do we have to come up to this reason, which seems artificial? – Because the walls of the ship are not made to enclose him, but rather to keep the water out.

What is the practical difference between the two explanations? – If the walls of the ship break, or if he jumps to another ship – he would be allowed to walk there only according to one explanation but not the other.

Art: Winslow Homer - Observations on Shipboard

Eruvin 41 – Residence area (techum)

Continuing with special days adjacent to each other, the Talmud discusses the fast of Tisha B'Av, commemorating the destruction of the Temple, which falls adjacent to Shabbat. Should one complete the fast and maintain his profound grief, or should he eat a little so as not to enter Shabbat while suffering? For example, Rabbi Akiva would eat a raw egg without salt. The final conclusion is that one should complete a full fast until it is definitely night, and only then start the Shabbat meal.

We already discussed that one may not leave his residence area on Shabbat and Festivals - about two thousand steps from his abode. It may be a city, a stand-alone house in a field, or just a personal space, four steps around himself if he happens to be outside in the open area. Thus, if he is alone in a Shabbat field, he may walk the four steps of personal space, plus a circle of two thousand amot (roughly, steps). This circle is called his "techum."

If gentiles removed him from his techum – he looses his residence area, and in the new place he can only walk four steps around but no more. The same holds true if he leaves his techum while being temporarily deranged. If they then returned him to his residence, he regains the complete techum, because he is not to be blamed or punished for what happened.

Tangentially, some things cause a person to go against his will and his Maker. Idolaters may force him to do wrong (like in the above example) and the pressure of poverty. Why do we need to know? – to pre-emptively pray to be spared. However, one who suffers from poverty and intestinal disorders in this world comes purified into the next one. Some also add here a bad wife.

Art: Thomas Benjamin Kennington - The Pinch of Poverty

Eruvin 40 – Conditional prayer

As we mentioned before, Rosh HaShanah is one day. However, because it is was not exactly known when the court will establish the first of the month (which was based on seeing the moon), Rosh HaShanah was celebrated for two days since very long ago. This is still true today, whether in Israel or outside. What does one say in prayer?

Rabbi Dosa says that one makes his prayer conditional: “Strengthen us on this new moon which is Rosh Hashanah, whether it is today or tomorrow.” On the next day, he adds, “Whether it is today or was yesterday.” If one does not phrase his prayer this way, it will contain a false statement. However, the Sages do not agree, saying that if you phrase your prayers conditionally, then the people will treat the holiday lightly and may do work on it.

Rabbi Dosa disagrees with the Sages on many points, and the Talmud enumerates them, adding that all of them had to be told. Otherwise, we might have though that the fear of treating the day lightly applies only on Rosh HaShanah, when people might transgress by doing work; by contrast, on the new moon work is permitted, so this prayer could be conditional – we are told that the Sages disagree here also, and require one form of prayer, without conditions.

Art: Francis Augustus Silva - Moonrise on the New England Coast

Eruvin 39 – Making conditions

Rosh HaShanah – New Year – is celebrated for two days. Even though the Torah, of course, decreed only one day of Rosh HaShanah, practically it was very hard to know when this day occurs – on the last day of the previous month, or the first day of the next one. So as not to do work on Rosh HaShana by mistake, people abstained from work on the first possible day of Rosh HaShana, and then also on the second.

If one wants to wants to go beyond two thousands steps in different directions on two days of Rosh Hashanah – he can, provided that he places his eruv food in appropriate places, since after all, only one day is the real festival – this is the opinion of Rabbi Yehudah. The Sages agree that it is one festival, but they argue that its long-term observance for two days made both days into one long Rosh HaShanah, so that he cannot have two different eruvs.

Rabbi Yehudah also allows to set other conditions for Rosh HaShanah. For example, if one has two baskets of fruit from which tithes have not been given, he can say on the first day of Rosh HaShanah, “If the festival is tomorrow, then I am separating tithes from one basket with the fruit from the other, but if the festival is today, I have not said anything.” Then he makes a similar condition on the second day and eats the fruit. Again, the Sages say it is all one long Rosh HaShanah. However, even the Sages allow such conditions to be made for the two days of a Yom Tov festival, since this second day is observed only outside of Israel and is thus not a universal requirement.

Art: James Peale - Fruit Still Life with Chinese Export Basket

Eruvin 38 – Eruv for two days

If two days that need an eruv follow each other in succession, then one has to worry about the eruv for each day. Rabbi Eliezer says that when a festival (yom tov) is followed by Shabbat, these are separate entities, and he can simply prepare two different eruvs, stating which way he wants to go based on each eruv.

However, the Sages say that two days of rest constitute one long entity, and one therefore cannot separate them. Here is the procedure that they recommend he should follow. At the beginning of the first day, which is a festival, he brings his eruv to the new place where he wants his new dwelling to be established. Then he waits until dark, acquires his new residence there, and now takes his food with him – out of fear that it may be consumed by wild animals. On the next day, he brings his eruv back, waits until night, and eats it (since on Shabbat he cannot carry it anyway). Because the food was present at the beginning of Shabbat, he has acquired his new residence there, and can walk two thousands steps in any direction from this place. He has thus acquired the possibility to walk the extra two thousand steps that he wanted, but was also able to benefit from his eruv food by eating it.

Art: by Jan van Kessel - Four Still Lives of Food and Fruit

Eruvin 37 – Changing the past

We learned about retroactive designation of an eruv, which changed the past depending on future events. Investigating this further, the Talmud quotes the rule about a barrel of wine.

If one buys a barrel of wine in Samaria, where many residents did not separate tithes, on Friday afternoon, so that he does not have the time to tithe, he can nevertheless prepare his wine for drinking with the following declaration. He says, “The two percent that I will separate in the future are hereby designated as 'terumah,' the Kohen's portion. The ten percent are Levites' tithe, and the other ten percent are for the poor.”

He then drinks the wine on Shabbat and leaves over the necessary amounts. Every drop that is left now was present somewhere in the barrel on Friday, so we can say that this same drop was  designated as tithe on Friday. Thus the future event of leaving some wine over determines the past designation of this wine as tithe. This principle is called “bereirah,” or “clarification”, and it is the opinion of Rabbi Meir. However, the other Sages did not agree with Rabbi Meir, asking him “What if the barrel breaks? He will have drunk untithed wine!” Rabbi Meir answered, “When it breaks, then we will worry about it.” What he really meant is that one can appoint a guardian to protect it. And the Sages? They say that the guardian himself may fall asleep, thus he needs another guardian, and so on, without end.

Art: Jan-Anton Garemyn - Canal scene with wine merchant unloading barrels

Eruvin 36 – Running away from a tax collector

When tax collecting was farmed out, and the collectors were, in fact, extortionists, it was common to avoid confrontations with them. If one fears a visit from a tax collector on Shabbat, he may increase the two thousand step limit that he is allowed to walk, to four thousand, in the following way. He can place two portions of eruv food in two places, one two thousand steps to the east and another – to the west. He can then make a stipulation, saying that if the tax collector comes tomorrow from the east, his west eruv takes effect, and if he comes from the west, then his east eruv is activated. If the collectors come from both directions, he will decide where to go, and his direction will determine the eruv, and if they don't come at all, neither of his eruvs are active, and he stays where he resides.

This is an example of the future affecting the present (bereirah). If the tax collector comes from the east in the future, then the west eruv is effective as of now. When tomorrow he actually comes, his future coming reaches into the past and changes the legal reality of the designation.

The same law applies when a man wants to hear a Sage coming with a lecture to a nearby town, and it is not known which town this will be. He makes two eruvs and makes a similar stipulation: if the Sage comes from the east, his east eruv is the one taking effect, etc. If two Sages come, he will decide which one he will go to. Rabbi Yehudah says that if one of the Sages is his teacher, he must go to him. Why? He might want to listen to another one!? – Some say that Rabbi Yehudah does not agree to the retroactive designation. In all other cases, Rabbi Yehudah explains that the Sage has already come – except that the man does not know to where. Others say that Rabbi Yehudah agrees to the retroactive designation but does not permit one's future decision to influence past reality.

Art: Paul Vos - The Tax Collector

Eruvin 35 – Eruv in a closet

If one locked his eruv food in a closet and then lost the key, the eruv is still valid. But why? It is not accessible! – It is a closet made of bricks, and he can break it, and in this way get to his food. But then he is demolishing, and that is prohibited on Shabbat!? – The closet is not cemented, it is just bricks put together.

If his eruv rolled beyond the “techum”, that is, the two thousand amot (about 2000 steps) that he is allowed to walk on Shabbat, then it is not valid. The same is true if it was burned or buried under a heap of rubble. Still, if this happened on the Shabbat day, it is not a problem, since the eruv already took effect on Friday night.

What if we don't know when the eruv food rolled out? Rabbi Meir says that since this is in doubt, then he is caught: he does not have his previous residence area (techum) and has not acquired a new one, so he has to stay put. However, multiple opinions said that a doubtful eruv is valid, and this became the law.

Art: Jean-Edouard Vuillard - Linen Closet

Eruvin 34 – Eruv too low or too high

If one placed his eruv food at the bottom of a pit, even hundreds feet deep, he eruv is still accessible to him and is therefore valid. Why do we need to be told this, it is obvious?! If the pit is in the private area – why, the pit is also a private area, and it goes all the way down and all they way up; thus, to get his eruv he does not need to transfer from a private to a public domain, and there is no prohibition in that. Rather, it must be that the pit is in the public area. But then he would not be allowed to get the food out, and the eruv would not be valid. Rather, it must be that the pit is in an area that is neither public nor private, and such transfers are prohibited only by the decree of the Sagse – which does not apply on Friday with the twilight, when the eruv takes effect! Thus, he can get his food at this time, and the eruv is valid.

If he placed his eruv food atop a reed or a pole, even hundreds of feet high, it is valid – provided that the reed was uprooted and later stuck back into the ground. Why being uprooted makes a difference? – In trying to remove his food from the reed's top, he may accidentally break off a piece, and in doing so he will perform the labor of reaping. This is prohibited even at twilight, when the eruv should have taken effect, and thus it never becomes valid.

Art: Niko Pirosmanashvili - A Boy Carrying Food

Eruvin 33 – Eruv on a tree

As we learned, one cannot go farther than two thousand steps away from his city of residence on Shabbat, and if he wants to go further, he needs an eruv – food that will symbolize that he moved his dwelling to this new place.

However, if he placed his eruv on a tree, he has a problem. The Sages prohibited taking objects from a tree on Shabbat, and therefore his eruv food is not accessible to him and is invalid. Nevertheless, the ruling is different and states that if the eruv is on a tree above ten hand-breadths from the ground, the eruv is indeed invalid, but if it is lower than that, it is valid.

How can we explain this? First, we are forced to say that this must be the opinion of Rabbi Yehudah the Prince, who says that at twilight the laws of the Sages do not apply. The tree is not muktzeh, and he can take his eruv. If so, why does ten hand-breadths make a difference? Well, the tree itself is similar to a house and is a private domain. When he takes his food from it and brings it to himself in the public domain, he violates Shabbat, and since he cannot do that, his eruv is invalid. However, below ten hand-breadths people usually do not carry, such area is called a “karmelit”, its prohibition is lighter, and his eruv is again valid.

Art: Vincent Van Gogh - Autumn Landscape with Four Trees

Eruvin 32 – One's dwelling on Shabbat

One Shabbat, one has to “stay in his place.” This means that he must imagine a circle around his dwelling, with the radius of two thousand amot (about half a mile) and never walk beyond the limit of this circle. A city is considered one's dwelling, so practically one can walk half a mile away from the city, but no more than that.

If he still needs to go further, he can change his dwelling place. For that, on Friday he can walk up to two thousand amot in the direction that he will have to go on Shabbat, and place food (“eruv”) there. This place then becomes his new “dwelling,” and he has to stay in the new circle. We thus find that he can go from his home to the new place, but not in the opposite direction, because this is where his new circle ends.

If he cannot go there on Friday to establish his eruv, he can send a messenger. However, if this messenger is a deaf-mute or deranged person, his eruv won't be valid, because they do not have the necessary understanding of the matter. On the other hand, if the deranged person only transports his eruv, but a sound-minded person accepts it there, it is valid.

Art: Jacobus Vrel - Street Scene with Two Figures Walking Away

Eruvin 31 – Marginally valid foods

There are foods that are somewhat prohibited but that can still be used for a Shabbat eruv - communal food which permits them to carry in an alley. For example, if he bought fruit in the market and has a doubt if the tithes were properly separated, he can still use this for an eruv – since poor people can eat it, and he can make himself poor by renouncing all his possessions.

However, if the food is definitely not tithed, then it cannot be used for an eruv, because one is not allowed to tithe on Shabbat, and thus the food is not edible by anybody.

A similar list of of foods is found in many places in the Talmud, for example, it applies to the laws of a communal prayer after a meal: one who ate doubtfully tithed produce may be joined in this prayer, but one who ate definitely untithed produce cannot.

Art: George Walter Harris - Summer fruits

Eruvin 30 – Common food (eruv)

In order for people to carry in an alleyway, they must not only place a crossbeam across the alley's opening, but also place some common food (eruv) in a designated place, to indicate that they are now one family and even combine their meals.

Any kind of food can be used for the eruv, except for water and salt – since they do not properly nourish. Incidentally, one who vowed to abstain for nourishment can still drink water and eat salt. The food does not have to be edible by the owner, as long as others can eat it. For example, one can make an eruv of wine for a nazirite: even though he is prohibited to drink wine, others can. Similarly, one can make eruv of terumah (Kohen's portion) for a regular Jew: even though he cannot eat it, but a Kohen can.

One can make an eruv with meat cooked rare – since some people eat it, and with raw eggs – again, since they are eaten under certain circumstances. How many eggs would be needed? Since the eruv should be sufficient for two meals, two eggs will constitute an eruv.

Art: Albert Neuhuys - Dinner time

Eruvin 17 – Fence of ropes

Another possibility to spend Shabbat in a caravan in a desert is to surround it with ropes: they can stretch three ropes at a distance of three hand-breadths from each other. If the thickness of the ropes together adds up to a hand-breadth, then they have a valid fence ten hand-breadths high. They could also surround their camp with vertical poles, ten hand-breadths high, and place them at three hand-breadths from each other.

How does this work? It relies on the principles of “Closing”, “Lavud” in Hebrew, which states that a gap of three hand-breadths can be considered closed for the purposes of Shabbat, ritual purity, and other similar laws where partitions are involved.

However, there are those who disagree. Rabbi Yehudah limits the partition of ropes only for a caravan of three or more people. His son Rabbi Yose is even more strict: he says that any partition that does not have criss-cross elements is not a partition. The Sages, however, say that a partition can be either vertical or horizontal.

Wait a minute! The Sages are repeating themselves!? – This is another group of Sages, and they differ with the first one in permitting such partition even for an individual at home, not in a desert.

Art: Francesco Peluso - An Algerian Caravan At Rest

Eruvin 16 – Shabbat in a caravan in the desert

If a caravan encamps in an open field, one cannot carry inside the caravan's area on Shabbat. Since this area lacks partitions, the Sages gave it the status of “karmelit”, which is neither private nor public, but still one cannot carry there. Therefore, they may decide to make a fence around the caravan. Then the following rules apply.

If they surrounded their encampment with saddles, saddlebags, and the like, then they can carry there – provided that the height of the partition is at least ten hand-breadths, that the gaps between the saddles are not larger than the total length of their fence. In addition, each individual gap should not be larger than ten amot (about 20 feet), since such a gap is considered a door. More than this is considered an opening, and then one cannot carry there.

What if the length of the gaps is exactly equal to the total length of the closed fence? Is such partition valid or not? The Talmud spends a page trying to find a proof. In the end, since the verbiage of our ruling above is most easily understood if we assume that gaps equal to fence are valid, this become the law.

Art: Edwin Lord Weeks - Arrival Of A Caravan

Eruvin 15 - Abaye wins

If a side-post was not erected specifically for observing Shabbat laws, but just happened to be there, will it work to permit carrying in the valley? Abaye says that it will – if they relied on it at the beginning of Sabbath – after all, they relied on it! However, Rava says that it does not help, since it was not made expressly for this purpose from the beginning. The Talmud lists a number of possible arguments pro and con, but Rava and Abaye remain unconvinced. The law, however, uncharacteristically follows Abaye – the side-post helps – and this is the "L" in the six cases abbreviated Y A L K G M where the law follows Abaye against Rava.

The side-post can be made of any material, and it can even be an animal. Here, however, Rabbi Meir disagrees – since anything that is alive cannot serve as a partition, according to him. Correspondingly, the Sages will say that an animal that is used as a coffin cover will become ritually impure, and Rabbi Meir will say that it won't. Tangentially, one can write a divorce document on an animal – but Rabbi Yose does not allow this. What are their reasons? Rabbi Yose says that the divorce document, or Get, is called in the Torah “The book (sefer) of separation.” Just as a book is not alive and does not eat – so must be the material for the divorce document. And the Sages? They understand the word “sefer” as “story,” which can be written on anything.

Art: Caspar David Friedrich - Landscape with Grave, Coffin and Owl

Eruvin 14 – The crossbeam has to be real

The crossbeam that fixes an alley for carrying on Shabbat – and which was the subject of many a discussion hithertofore – has to be real: it needs to be able to support at least a half of a standard brick, which amounts to a hand-breadth; Rabbi Yehudah says that it only has to look right, not to be strong. What is the source for their disagreement? – The first teacher considers the crossbeam to be a reminder, thus, it has to be somewhat serious; Rabbi Yehudah says it is a symbolic fourth wall, and only has to look right.

By contrast, if one uses a side-post to delineate where the alley ends and the street begins – that side-post only has to be ten hand-breadths high, but it can be as thin as a thread. A side-post is more unusual than a crossbeam, and thus serves its purpose, whether as a symbolic wall or as a reminder.

Art: Vasily Perov - Three Apprentice Workmen Carrying Water