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Lesson 20: Tying and Untying Knots on Shabbos
Welcome to Lesson 20. In this lesson, we’ll talk about two of the 39 melachos (prohibited acts) of Shabbos (Shabbat): the melachah of Koshair (קושר)—tying knots—and the melachah of Matir (מתיר)—untying knots.
The basic idea is this: one is not allowed to tie a certain type of knot on Shabbos, and similarly, one is not allowed to untie that type of knot on Shabbos.
So what does that mean practically? Does that mean I’m not allowed to tie my shoes on Shabbos? Am I not allowed to tie the belt on my robe on Shabbos?
Let’s look at examples so we can see clearly which knots are permitted and which knots are not allowed to be tied on Shabbos.
What Type of Knot is Prohibited?
When discussing the melachah of Koshair, the definition given by the rabbis is a kesher shel kayama—a permanent knot.
There are many different opinions among the early poskim (rabbis of Torah law) about what qualifies as a kesher shel kayama:
- Which knots are prohibited by Torah law
- Which are prohibited rabbinically
- And which knots are fully permitted
The goal of this lesson is to cut through all of that and get practical: what should a person do in their home on Shabbos to avoid the melachos of Koshair (tying) and Matir (untying)? What’s the practical halachah?
Knots You May Tie on Shabbos
Slip Knots
A slip knot—a knot that can be undone by pulling one end—is permitted.
Example:
You’re cleaning up after the Shabbos meal and want to store some leftover challah in a plastic bag. You put the challah into the bag and tie it with a slip knot. It will stay closed and keep the challah fresh, and when you want to open it, all you have to do is pull one end and it comes undone. That may be done on Shabbos.
Similar but prohibited is tying the plastic bag into itself in a way that it doesn’t just slip open. That’s not a slip knot. You can’t simply pull the end to undo it—you have to untie the actual knot. This is a real knot and should not be done on Shabbos.
When a Knot Becomes “Permanent”
Let me give you a real-life example. On Friday, I went shopping and bought tomatoes. The cashier tied the bag into a simple, tight knot—the kind you can’t just pull open, and is not permitted on Shabbos.
Most people, when unpacking, don’t bother untying that knot. It’s easier to just tear the bag open. That’s a sign that the knot is likely not going to be undone. It takes on an air of permanence. That could be considered a kesher shel kayama.
So what do you do if you want to eat those tomatoes on Shabbos? Don’t untie the knot—tear open the bag and take the tomatoes out. That’s fine. But don’t make that type of knot on Shabbos.
Robes, Coats, and Belts
You’re going to shul on Shabbos. You put on your coat, and want to tie the belt. If you tie it once, that’s okay—it’s not tight, it’s not permanent.
You want to double it, tie it twice? Normally, a double knot would be a problem. But in this case, you’re just going for a walk or heading to shul. When you get there, you’re going to take it off and untie it right away. You don’t tie it tightly—it’s loose, and it’s made to be undone soon.
So even though it’s a double knot—normally a no-no—since it’s:
- Loosely tied
- Meant to be undone shortly
- Not intended to last
…it’s permitted. That applies to robes, coats, anything similar.
What About Shoes?
Most people tie their shoes when they put them on and untie them when they take them off. It’s not a kesher shel kayama – there’s no permanence to that tie.
So you make a knot, put a bow on top—that’s what most people do. It’s made to be untied within 24 hours, has no air of permanence, so it’s permitted on Shabbos.
But what if you’re a little lazy? You don’t untie your shoes when taking them off—you just slip them off and leave the knot in place overnight. Then you slip them back on in the morning.
Now you’ve made a knot that’s not intended to be untied. You shouldn’t make that knot on Shabbos. If you make this knot, and your shoes come untied and you need to retie them, make sure this time you untie them when you take them off. Otherwise, if you go several days before untying, it may be considered a prohibited permanent knot.
You should not double the knot—that makes it much more permanent. However, it isn’t so clear that a double knot on your shoelaces is prohibited, as it’s made only to be temporary.
Untying Children’s Shoes
So let’s say you tied your child’s shoes in a double knot Friday afternoon. Now it’s Friday night, they are going to sleep, and they can’t get it off!
They’re crying, they’re uncomfortable. The knot wasn’t made with full permanence—it was just to keep the shoes on better. In a case of difficulty or pain, even though it was a knot that shouldn’t have been made- which would normally mean that it can’t be untied on Shabbos- in this case it’s permitted to untie, as it’s not so clear that it’s really a permanent knot, given that it was tied with the intention to undo it.
But the right way to do it from the start? A bow over a knot. Tie it that way and untie it when taking the shoes off. That’s the best way to do it on Shabbos.
Garbage Bags
Now let’s talk about garbage.
You have a garbage bag with drawstrings. On Shabbos, you can pull the strings tight. That’s fine.
What would you do during the week? You’d probably tie it closed with a double knot. But on Shabbos, you can’t do that.
Just tie it once and pull the strings—don’t go any further. Don’t tie a double knot or even a bow on top. That creates a knot that won’t be untied—a permanent.
If you have non-drawstring bags, all you can do is tie it once, but don’t tie it in a knot, or even with a bow. It gives off an air of permanence and shouldn’t be done.
This comes up all the time at shul during kiddush. People clean up and instinctively tie the garbage bags tightly. Don’t do that. Just tie it once and set it aside.
Tzitzis and Frayed Strings
Another example: a man comes to shul on Shabbos and checks his tzitzis. He notices the knots are loose. His first instinct is to tighten them.
But just like you can’t tie a new knot on Shabbos, you also can’t tighten one. That’s considered securing a knot—equivalent to tying it.
Also, let’s say one of the strings is fraying. You want to tie a knot to stop it from unraveling, as if it unravels on the way, it won’t be considered a string. During the week, you should absolutely do that.
But don’t do it on Shabbos. That small knot, meant to stop the fraying permanently, is a form of kesher shel kayama and is at least rabbinically prohibited.
In Conclusion
In the merit of observing these laws of Shabbos—knowing what to tie, what not to tie, how to tie, and how to untie—may we be zocheh to what Chazal (our sages) say:
If Klal Yisrael (all of the Jewish nation) keeps two Shabbosos in a row, we’ll merit the coming of Mashiach.
May it be speedily in our days. Amen.
Rabbi Pinchus Rappaport is a respected rabbi who received his Rabbinic ordination from Yeshiva of Staten Island, under the tutelage of Rabbi Moshe Feinstein. He currently serves as a rabbi in Brooklyn, NY.
Since halachic opinions vary among the rabbis of different communities, Oorah and Rabbi Rappaport encourage you to direct any questions to, and get halachic guidance from, your local Orthodox rabbi. You may, however, rely on this video and email Rabbi Rappaport with questions in the interim, at askrpr2@gmail.com.
Shared as a zechus l’iluy nishmas Moshe Zeev ben Aryeh Leib
