The Sages of the Mishnah and the Talmud 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
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. 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.
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), since foods and other items put into plastic bags often
remain in them for several days. [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 (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
Sefer Torah: Some poskim 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. 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.
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.
Tzitzis: It is forbidden to knot tzitzis strings to a tallis on Shabbos, or
even to tighten the existing knots if they became loose, even if one
intended to untie the knots within 24 hours. 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.
Plastic (or paper) twist ties: Some poskim 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 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,
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.
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.
1. Shabbos 111b.
2. Mishnah Berurah 317:29.
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. Rama, O.C. 317:1 and Aruch ha-Shulchan 317:10.
5. Mishnah Berurah 317:15.
6. Mishnah Berurah 317:29.
7. Mishnah Berurah 651:11.
8. Rama, O.C. 651:1 and Mishnah Berurah 11.
9. 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.