Talmud - Eruvin 58a עירובין נ״ח א׳

provided he does not thereby go out beyond the city’s Shabbat limit, as those watching the surveyor might mistakenly think the limit extends to that point.

If, due to the width of the canyon or hill, he cannot span it, with regard to this situation Rabbi Dostai bar Yannai said in the name of Rabbi Meir: I heard that one may pierce hills. In other words, one measures the distance as if there were a hole from one side of the hill to the other, so that in effect, he measures only the horizontal distance and ignores the differences in elevation.

GEMARA: The Gemara asks: From where are these matters, that the Shabbat limit must be measured with a rope fifty cubits long, derived? Rav Yehuda said that Rav said: They are derived from that which the verse states: “The length of the courtyard shall be one hundred cubits, and the breadth fifty by fifty” (Exodus 27:18). The Torah states: Measure with a rope of fifty cubits, i.e., the length and breadth of the courtyard must be measured “by fifty,” with a rope fifty cubits long.

The Gemara asks: This repetitive usage of the word fifty is necessary to teach us something else, namely, that the area of a courtyard is equivalent to a square the size of the Tabernacle’s courtyard. To this end, the Torah states: Take a square of fifty cubits by fifty cubits, and surround it with the remaining fifty cubits in order to form a square, each side of which is just over seventy cubits long.

The Gemara answers: If so, let the verse state: Fifty, fifty, which would have sufficed to teach us the size and shape of a courtyard. What is the significance of the phrase: Fifty by fifty? Conclude from this that the verse comes to teach two things, both the matter of the square courtyard and that the length of the rope used to measure the Shabbat limit should be fifty cubits long.

We learned in the mishna: One may measure a Shabbat limit only with a rope fifty cubits long, not less and not more. It was taught in the Tosefta: No less, because a shorter rope improperly increases the Shabbat limit, as the rope is likely to be stretched. And no more, because a longer rope reduces the limit, as the rope is likely to sag due to its weight.

Rabbi Asi said: One may measure only with a rope of afsakima. The Gemara asks: What is afsakima? Rabbi Abba said: It is the nargila plant. This name was also not widely known, and therefore the Gemara asks: What is nargila? Rabbi Ya’akov said: A palm tree that has only one fibrous vine wrapped around it. Some say a different version of the previous discussion, according to which the Gemara asked: What is afsakima? Rabbi Abba said: It is the nargila plant. Rabbi Ya’akov disagreed and said: It is a palm tree with one fibrous vine.

It was taught in a baraita that Rabbi Yehoshua ben Ḥananya said: You have nothing better for measuring than iron chains, as they do not stretch. But what shall we do, as the Torah states: “I lifted up my eyes again and looked, and behold a man with a measuring rope in his hand” (Zechariah 2:5), from which it is derived that measurements must be made with a rope.

The Gemara asks: Isn’t it also written: “And in the man’s hand a measuring reed of six cubits long, of one cubit and a handbreadth each” (Ezekiel 40:5), which indicates that reeds may also be used for measuring? The Gemara answers: That is used for measuring gates, which are too narrow to be measured with lengthy ropes.

Rav Yosef taught that there are three kinds of rope, each required by halakha for a different purpose: A rope of magag, a kind of bulrush reed; a rope of netzer, made from fibrous palm vines; and a rope of flax.

They are used for the following purposes: A rope of magag is utilized for the burning of the red heifer, as we learned in a mishna: They would bind the heifer with a rope of magag and place it on its woodpile, where it would be burned after it was slaughtered. A rope of netzer was required for a sota, a woman suspected of adultery, as we learned in a mishna: Before the sota is compelled to drink the bitter waters, her clothes are torn. And after that a priest brings a mitzri rope, i.e., a rope made of reeds [netzarim], and binds it above her breasts, so that her garments will not fall. A rope of flax is used for measuring.

It was stated in the mishna: If he was measuring the limit and he reached a canyon or a fence, he spans the area as if it were completely flat and then resumes his measurement. The Gemara comments: From the fact that it taught that he resumes his measurement, it may be derived by inference that if he cannot span it because it is too wide, he goes to a place where it is narrower so that he can span it. And he spans it, and he then looks for the spot at the same distance that is aligned with his original measurement, and he resumes his measurement from there.

The Gemara comments that we have indeed learned this, as the Sages taught the following baraita: In the case of one who was measuring the Shabbat limit and the measurement reached a canyon, if he can span the canyon with a rope of fifty cubits, i.e., if the canyon is less than fifty cubits wide, he spans it. And if not, i.e., if the valley is more than fifty cubits wide, he goes to a place where it is narrower so that he can span it, and he spans it, and he then looks for the spot at the same distance that aligns with his original measurement, and he resumes his measurement from there.

The baraita continues: If the canyon was curved so that it surrounds the city on more than one side, and it cannot be spanned on the side where he wishes to measure the limit, he pierces and ascends, pierces and descends, thereby measuring the canyon’s width bit by bit. If he reached a wall, we do not say that he should pierce the wall so that it can be precisely measured; rather, he estimates its width and then leaves and continues on.

The Gemara asks: Didn’t we learn in the mishna: If he reached a canyon or fence, he spans it and then resumes his measurement? Why is a precise measurement required there, whereas in the case of a wall, an estimate is sufficient? The Gemara explains: There, in the mishna, we are dealing with a place whose use is convenient, i.e., where the slope is relatively gentle so that the area can be crossed. Therefore, the area must actually be measured. However, here, in the baraita, the wall’s use is not convenient. Since one cannot walk through the wall, an estimate of its width is sufficient.

Rav Yehuda said that Shmuel said: They taught the method of piercing only where a plumb line does not drop straight down, i.e., where the canyon has a slope.

Traduction : The William Davidson digital edition of the Koren Noé Talmud, with commentary by Rabbi Adin Even-Israel Steinsaltz.

Eruvin 58a examines measuring Shabbat boundaries with a fifty-cubit rope, deriving this rule from Tabernacle courtyard dimensions in Exodus.