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 “labor” 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 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 length of time the knot must remain knotted in order for it to be considered permanent; the halachic differences between a knot tied by a professional (“craftsman”) and one tied by an amateur; 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—distress, 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 is intended to be undone within 24 hours. People who generally take off their shoes without untying the knot may not tie their shoelaces on Shabbos in this manner, unless they will be careful to untie the knot before 24 hours have elapsed[2].

A tight double knot, as is often tied on children’s shoes to prevent the shoe from slipping off, may not be made on Shabbos even if it is intended to be undone within 24 hours[3]. Still, in a case of distress (tza’ar), it is permitted to tie (or untie) a double knot on Shabbos, particularly if the knot is intended to be undone within 24 hours[4].

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[5]. 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), since foods and other items put into plastic bags often remain in them for several days[6]. [In the atypical case where the item is being placed in the bag for less than 24 hours, this knot is permitted.]

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 is intended to remain for 24 hours or more); 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.

Lulav: It is a mitzvah to tie the three minim—lulav, hadasim and aravos—together. This should be done on erev Succos, since it is forbidden to tie any knot (double knot; single knot with a bow; 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[8].

Sefer Torah: Some poskim[9] 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[10]. 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 avoid this potential problem altogether[11].

Belts, gartels, scarves and kerchiefs: These items may be tied with a knot and a bow, a knot with the ends tucked in, 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[12].

Tzitzis: It is forbidden to knot tzitzis strings to a tallis on Shabbos, or even to tighten the existing knots if they became loose[13], even if one intended to untie the knots within 24 hours[14]. Tying a single knot at the end of a tzitzis string (to keep it from unraveling) is also forbidden, as such a tight knot is considered like a double knot.

Bandage: Gauze may be tied around a cut—even with a tight double knot—if there is no other way of securing it, e.g. through clips or bows. This is permitted because in a situation of physical discomfort a double knot is permitted to be made, when necessary[15].

Plastic (or paper) twist ties: Some poskim[16] rule that it is prohibited to tightly twist (or untwist) a paper-covered or a plastic-covered wire twister around a bag and then repeatedly twist together its two ends. This ruling is based on the view of the Rambam[17] 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 together 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[18], it is recommended then one not twist “twisties” tightly. If the bag must be tightly sealed, then it is recommended that one twist the tie around the bag only once or twice and avoid doing so repeatedly[19].

Note: 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.

20. Mishnah Berurah 317:25.

Weekly-Halacha, Text Copyright © 2012 by Rabbi Neustadt, Dr. Jeffrey Gross and Torah.org.

Rabbi Neustadt is the Yoshev Rosh of the Vaad Harabbonim of Detroit and the Av Beis Din of the Beis Din Tzedek of Detroit. He could be reached at [email protected]