The fifteenth perek of Massekhet, which begins on today’s daf discusses two distinct topics – tying knots and the prohibition against preparing on
Shabbat for the rest of the week.
Regarding the first topic – the primary labors of tying and untying knots, the Gemara specifies, explains, and identifies these labors. Tying and untying, as is the case with regard to the labors of building and destroying, constitute a pair of labors for which one is liable for one labor only under the same conditions for which he liable for the other, e.g., one is liable for either tying or untying only if the knot is a permanent one.
To understand these labors, it is first necessary to clarify what constitutes a knot.
What are the types of knots that the Torah prohibited one to tie or untie on?
Several traditions were received by the Sages on this matter. They too require analysis and additional clarification.
There is a fundamental principle that one is liable for tying or untying only a permanent knot, i.e., a knot designed to endure. This requirement precludes knots made to be immediately undone as well as knots meant to be undone in the near future. The definition of permanence as it pertains to a knot requires further clarification. Does permanence relate to the function of the knot, the method by which the knot was tied, or both? If permanence relates only to the method of tying, it is only necessary to ascertain if a knot was tied in such a manner that it can endure for a long period of time. If so, the person who tied the knot is liable for his action, even if he intended for the knot to be temporary and planned to immediately untie it.
During this discussion, many sets of circumstances are described, including various types of knots and various uses of materials. Consideration is given to both knots tied in a common, simple manner and knots tied with utensils or parts of vessels, such as the knots of shoes, sandals, and the like. The central theme of this chapter is the qualifications of a knot for the purposes of both Torah law and rabbinic decree.