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Weekly Halacha

Parshas Lech Lecha

By Rabbi Doniel Neustadt

A discussion of Halachic topics related to the Parsha of the week. For final rulings, consult your Rav.


The Sages of the Mishnah and the Talmud(1) do not clearly define the exact parameters of the melachah of knotting, the twenty-first of the thirty-nine forbidden forms of "work" on Shabbos. The description of the Biblically prohibited knot, kesher shel k'yama, a permanent knot, is vague enough to allow for much dispute and debate among the Rishonim as to its exact identity. The debate focuses chiefly on the type of permanency required - must the knot be permanent in its intended duration, in its craftsmanship and quality, or in both? This discussion ultimately leads into its natural extension - the definition of a Rabbinically prohibited knot. Several other issues are debated among the poskim, such as the amount of time the knot must remain knotted in order for it to be considered permanent; the halachic differences between a professional ("craftsman's") knot and an amateur one; the status of a bow, etc.

Although some of these issues are ruled on definitively, others are not. Consequently, there are various opinions as to the practical halachah. Sometimes, the poskim take into account special circumstances-acute physical discomfort, a pressing need to fulfill a mitzvah, etc. To better understand the practical applications of the halachos, we have listed some daily activities which involve this melachah:

SHOELACES: Shoelaces are usually tied with a "single knot" [technically, an "overhand" knot, the first stage of tying shoes] followed by a bow. It is permitted to tie a shoelace in this manner provided that the knot will be undone before 24 hours have elapsed(2). A tight double knot, however, as is often tied on children's shoes to prevent the shoe from slipping off, may not be made on Shabbos even if it will be undone on the same day(3). In a case of acute physical discomfort, there are opinions(4) which allow a double knot to be made on Shabbos, even if the knot will not be undone before 24 hours have elapsed(5).

PLASTIC BAGS: It is prohibited to twist the top of a bag, make a loop, pull the top through the loop and tighten it to form a knot. This type of knot is considered like a double knot which is prohibited. It is also forbidden to take the two top corners of a plastic bag, tie them and make a bow [as if tying a shoelace]. This type of knot is prohibited since foods and other items put into plastic bags usually remain in them for several days(6). There are, however, two permissible ways of knotting a plastic bag on Shabbos: 1) Making a single [overhand] knot only, by taking the two top corners of a plastic bag and tying them [like the first stage of tying a shoelace]. Since such a knot will unravel even without manipulation, it is not considered a knot at all. After the single knot has been tied, one may not take the corners of the bag and tuck them under the single knot, since that strengthens the knot(7) [just as a bow, which strengthens the knot, may not be made over a single knot if the knot will not be undone before 24 hours have elapsed]; 2) Making a slip knot [a loop which is not completely pulled through and does not form a knot] at the top of the bag. This is not considered a knot but a bow.

PLASTIC [or paper] TWIST TIES: Some poskim(8) rule that it is prohibited to twist [or untwist] a paper-covered or a plastic-covered wire twister around a bag and then twist together its two ends. This ruling is based on the view of the Rambam(9) that one who twists two threads together is producing a rope and transgressing the melachah of knotting. According to this view, twisting the two ends of a twist tie together is similar to twisting two threads to make a rope and may very well be prohibited. Although other poskim maintain that the two cases are not comparable and it is essentially permitted to twist these ties(10), it is still recommended by some that, if possible, it is better not to use twist ties on Shabbos(11).

LULAV: It is a mitzvah to tie the three minim - lulav, hadasim and aravos - together. This must be done on erev Sukkos, since it is forbidden to tie any knot [double knot, overhand knot, single knot with a bow, or single knot with the ends tucked in] around a lulav on Shabbos or Yom Tov. The only solution for one who failed to prepare his lulav in advance is to wind a lulav leaf, etc., around the lulav, hadasim and aravos, make no knot whatsoever, but merely wind around and around so that the hadasim and aravos are "wrapped" around the lulav. The ends of the lulav leaf, etc., may be tucked in. Tucking in the ends is permitted in this case because no knot at all was made(12).

SEFER TORAH: Some poskim(13) rule that it is prohibited to make a single knot and a bow [or a single knot with the ends tucked in under the band] when putting away the Sefer Torah on Shabbos at the Minchah service. Since this knot will remain intact for over twenty- four hours, it should not be made on Shabbos. The custom in most places, however, is to be lenient, and many poskim accept the leniency(14). Another option is to wind the band around the Sefer Torah without making any knot at all, and then tuck the ends under the band, as explained earlier in the case of a lulav which is bound on Yom Tov. Those congregations that use a band with metal clasps or a special band called a wimple(15), avoid this potential problem altogether.

BELTS AND KERCHIEFS: These items may be tied with a knot and a bow, or a loose double knot, since these knots are not normally tightened, and even if they are tightened, they are usually loosened within 24 hours(16).


1.Tying a single knot at the end [or in the middle] of a string as is often done at the ends of tzitzis strings [to keep them from unraveling], is considered a prohibited [double] knot, since this type of knot is tight and permanent.

2. It is forbidden to make a knot on top of an existing knot(17), or a third knot on top of a double knot, since the third knot strengthens the entire knot(18).

3. A bandage may be tied around a wound - even with a tight double knot - as long as the intention is to remove it within seven days and there is no other way of securing it [e.g. through clips or bows]. This, according to many poskim, is a case of acute physical discomfort which may be alleviated by tying a knot(19).

4. When absolutely necessary, a non-Jew may be asked to tie a knot - even a tight double knot - provided that the knot is not intended to be "permanent" - to last indefinitely(20).


1 Shabbos 111b.

2 Mishnah Berurah 317:29. Therefore, when one removes his shoes, he must untie the laces, not merely slip the shoes off.

3 Mishnah Berurah 317:14. See Chazon Ish O.C. 52:17 who refers to this prohibition as a "chumrah b'almah" which has become the custom.

4 See Rama 317:1 who allows the untying of a double knot when in tza'ar. It remains unclear why Rama did not discuss tying under such circumstances. Some poskim suggest that there are not many cases where tza'ar can be alleviated by tying -see Menorah ha-Tehorah 317:8, while other poskim explicitly permit tying a double knot in case of tza'ar -see Aruch ha-Shulchan 317:10.

5 Rama's exact language is "tza'ar". We have chosen to translate that as "acute physical discomfort" based on Beiur ha-Gra's (see Damesek Eliezer) comparison of this tza'ar to the tza'ar caused by an insect bite, which is discussed in O.C. 316:9. Surely, tying children's shoes so that they do not slip off is not an example of such "tza'ar."

6 Shemiras Shabbos K'hilchasah 9:16; Rabbi P.E. Falk (Zachor v'Shamor, knotting, pg. 16).

7 Mishnah Berurah 651:11.

8 Harav S.Z. Auerbach in Shemiras Shabbos K'hilchasah 15, note 166 and in Tikunim u'Miluim; Shemiras Shabbos K'hilchasah 9:13; Rabbi P.E. Falk (Zachor v'Shamor, Knotting, pg. 16). See also Me'or ha-Shabbos, vol. 3, pg. 427.

9 Quoted in Mishnah Berurah 317:34. Other Rishonim, however, do not agree that this is prohibited -see Beiur Halachah 314:8.

10 Oral ruling heard in the name of Harav M. Feinstein (quoted in The Shabbos Home, pg. 223). See Igros Moshe O.C. 2:84 for a possible explanation.

11 Shevet ha-Levi 8:55; Harav Y. Roth (Ohr ha-Shabbos vol. 10, pg. 20).

12 Rama O.C. 651:1 and Mishnah Berurah 11.

13 Minchas Shabbos 80:155. According to this view, it is also prohibited to knot a Sefer Torah band in this fashion on Thursday, since it has be untied on Shabbos morning.

14 Ketzos ha-Shulchan 123:9; Tzitz Eliezer 7:29; Harav S.Z. Auerbach quoted in Shemiras Shabbos K'hilchasah 15 note 178.

15 Used mainly in German congregations. According to Harav S. Schwab (quoted in Knots on Shabbos), this type of band was introduced in order to avoid the issue of knotting on Shabbos.

16 Sha'arei Teshuvah 317:1 according to the explanation of Kaf ha-Chayim 317:23 and Shevet ha-Levi 8:60; See also Badei ha-Shulchan 123:4; Toras Shabbos 317:2 and Shemiras Shabbos K'hilchasah 15 note 167 quoting Harav S.Z. Auerbach.

17 Maharsham 6:34.

18 Harav S.Z. Auerbach quoted in Shemiras Shabbos K'hilchasah 15:51. See, however, Tikunum u'Miluim where he modifies his decision and remains undecided.

19 See Shemiras Shabbos K'hilchasah 15:52.

20 Mishnah Berurah 317:25.

Weekly-Halacha, Copyright © 2002 by Rabbi Neustadt, Dr. Jeffrey Gross and Project Genesis, Inc.

Rabbi Neustadt is the principal of Yavne Teachers' College in Cleveland, Ohio. He is also the Magid Shiur of a daily Mishna Berurah class at Congregation Shomre Shabbos.

The Weekly-Halacha Series is distributed L'zchus Hayeled Doniel Meir ben Hinda. Weekly sponsorships are available--please send email to the moderator, Dr. Jeffrey Gross

The series is distributed by the Harbotzas Torah Division of Congregation Shomre Shabbos, 1801 South Taylor Road, Cleveland Heights, Ohio 44118--HaRav Yisroel Grumer, Marah D'Asra



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