Commento su Shabbat 15:1

אלו קשרים. קשר גמלים – they perforate the nose of a camel and place in it a strap and tie it an eternal knot and like this, they make a perforation at the head of as ship and place in it a rope and tie a durable knot in it can never be undone, that is similar to knots of threads of curtains that have torn in the Tabernacle, but a durable knot that is not the act of an artisan, or it is the act of an artisan but is not durable knot is exempt, but prohibited and it is not liable until it is one of durability and the action of an artisan.

Introduction This mishnah and the following one deal with the prohibited labors of tying and untying. As we shall see in the mishnah, one is liable only if the knot is one that is intended to last.

וכשם שחייב על קשרן כך חייב על התירן – for just as those who hunt snail/conchiferous animal/purple-fish it would be necessary on occasion to undo/loosen the knots of the nets that exist in order to shorten them or widen them.

These are the knots for which a person is liable? Camel-drivers’ knots and sailors’ knots. And just as one is guilty for tying them, so one is guilty for untying them. Rabbi Meir says: any knot which one can untie with one hand they are not liable for it. Camel-drivers would tie ropes to their camels’ noses and the ropes would remain permanently attached to the camels. Similarly, sailors would permanently tie their ropes to their ships. Since these knots are intended to remain in their place for good, one who ties are unties such a knot is liable. Rabbi Meir states a different criterion for determining whether a given knot entails liability. If one can untie the knot with one hand it is not a knot which entails a liability, even if it is intended to remain permanently in its place. It is interesting to note that according to the first opinion, what determines liability is intent if it is intended that the knot remain forever then one is liable. In contrast, the physical nature of the knot is, according to Rabbi Meir, what determines liability. This is a debate we have often noted in the Mishnah is the halakhah determined by the physical nature of an act or by the intention with which the act was performed.

שיכול להתירו – without being squeezed/pricked.

אין חייבין עליו – and even if he did to make it durable, but the Halakha is not according to Rabbi Meir.