פירוש על שבת 17:4

מסר גדול - a large saw that we saw boards.

Introduction This mishnah provides some general rules concerning which vessels may be carried on Shabbat and when they may be carried.

ויתד של מחרישה – a large utensil made like a knife with which they make a incision of a turn of the plough/furrow’s length and they are strict with him and designated for them a place that is not worthy for any other labor.

Rabbi Yose says: all vessels may be carried, except a large saw and the pin of a plough. The reason that one may not carry a large saw or the pin of a plough is that people are very careful not to ruin these things. Since they are so careful with these things, they won’t use them for other purposes, and since the normal use of these things is prohibited on Shabbat, they may not be carried at all.

כל הכלים ניטלים לצורך ושלא לצורך – this is how it should be understood: All the utensils whose labor is for permitted things such as plates and cups which are removed [on the Sabbath] for the necessity of its own body as well as for the necessity of the place of the utensil, as well as that which is not necessary, even if he doesn’t need the implement nor the place of the utensil, other than to carry it on account of the shade or that thieves should not steal it, it is permitted with a utensil that whose labor is something permitted. But a utensil that is used for some kind of prohibited labor, such as mortars and millstone and similar things for its own necessity and for the needs of its place, it is permitted, but from the sun to the shade or because of thieves, it is prohibited.

All vessels may be carried whether required or not required. Rabbi Nehemiah says: they may be handled only for what is required. According to the first opinion in the mishnah, all vessels may be carried whether there is a need for them or not. In the Talmud there is a debate what it means when the mishnah says they are “not required.” According to one explanation, “not required” means that the person doesn’t want to use the vessel itself, but rather wants to move it away from its current place. For instance, I might want to move a knife not to use the knife to cut something but to keep it away from my child. According to this explanation, there must be some purpose to moving the knife. Another explanation is that “not required” means that the person is carrying it for no reason whatsoever. Our explanation of this clause will impact our explanation of Rabbi Nehemiah’s debate. According to the first explanation, Rabbi Nehemiah forbids carrying the object unless the object itself is needed. For instance, a knife may be carried only if one wants to use the knife itself. According to the second explanation, Rabbi Nehemiah would allow carrying the knife even if one only wants to move it to clear it from its current place. He would forbid moving the vessel only if there was truly no purpose to doing so.

רבי נחמיה אומר אין ניטלין אלא לצורך – It is explained in the Talmud (Talmud Shabbat 124b) for the needs of its unique use alone but not for the needs of something else, even for its own needs, such as a knife to cut with alone, it is permitted, and not to support with it the bowl. But the Halakha is not according to Rabbi Nehemiah.