Keilim, Chapter 15, Mishnah 4. Our mishnah turns to a small but revealing detail of utensils: the loop or cord attached to a keli so that it can be hung up on a peg or a wall. Is that loop considered part of the utensil, so that when the utensil contracts tumah the loop is tamei along with it, or is it merely an accessory riding along on the keli without truly belonging to it? The answer depends on a principle that runs through much of Masechet Keilim: what makes something part of a keli is not being physically joined to it, but sharing in its work.
Rebbi Meir: the loops are tamei
"Kol hateluyim teme'in": all the hanging loops attached to utensils are susceptible to tumah. Since the loop is joined to a keli that can itself become tamei, the loop is drawn in with it and becomes tamei as well.
Rebbi Meir then names two items that fall outside this rule: "chutz mitelui nafa uchvara," apart from the loop of a nafa and of a kevara, when they belong to a "baal habayit," a private householder rather than a tradesman. A nafa is used to sift flour; a kevara is perforated with wider holes and serves to clear debris out of grain. In a private home these two implements are constantly borrowed for other jobs, and their loop is therefore untied and tied on again as circumstances require. Whatever is put on and taken off in this way is never permanently wedded to the utensil, and halachah does not reckon it a component of the keli. Consequently, even during a stretch when the loop happens to be in place and the utensil contracts tumah, the loop itself remains clean. "Divrei Rebbi Meir": such is Rebbi Meir's ruling.
The Hachamim: the loops are tahor
"Vahachamim omrim: kulam tehorin." The Hachamim reverse the presumption entirely. In their view all such loops remain pure. A loop is not part of the keli, and even while it is attached to it, it does not perform the utensil's function. Not sharing in the work of the keli, it is not counted as part of the keli, and it does not contract tumah.
But the Hachamim also carve out exceptions, four cases in which the loop truly is susceptible to tumah, because there the loop takes part in the labor of the utensil.
1. The loop of the professional's flour sifter
The first case is a "telui nafa shel salatin," the loop on the sifter of a salatin, a dealer in flour. His sifter is built on a large scale to handle commercial quantities.
2. The loop on a threshing floor kevara
"Utelui kivrat geranot" points to the loop on the kevara used out on the granot, the threshing floors, where the harvested produce still has to be cleared of its chaff and straw.
These opening two cases go together. Both involve outsized tools that handle heavy loads of grain or flour. An implement of such bulk would be propped on a pair of wooden supports, filled with its load, and then rocked to and fro until the contents dropped through the openings. When the worker's arms began to tire, he would thread his hands into the loops while shaking the implement, and they gave him added leverage. The loop is thus doing part of the utensil's job.
3. The loop of the hand sickle
"Utelui magal yad" refers to the loop fastened to a metal hand sickle, the tool with which standing grain is cut. A sickle is itself a metal keli, and metal utensils are susceptible to tumah even when they form no receptacle at all. Here again the loop shares in the labor: while the reaper pulls the blade this way and that, he slips his hand through it so that the sickle will not fly out of his grip.
4. The loop of the searcher's stick
"Utelui makal habalashin": the loop of the metal rod carried by a tax collector. Such an official would go about with a metal staff to probe a person's property and goods, checking whether anything taxable had been concealed. He would drive the rod deep into a pile of straw, for instance, to discover whether wheat was hidden beneath it. The loop served him in this work: his hand went through it so that the rod would not slide from his grasp as he probed.
The reason and the rule
All four are tamei "mipenei shehein mesaye'in bish'at hamelacha," because these loops assist the utensil at the time it is being used. Since the loop participates in the utensil's function, it takes on the utensil's status and is susceptible to tumah just as the keli itself is.
The mishnah then formulates a governing principle, "Zeh hakelal," this is the rule. A loop "he'asui lesayei'a bish'at melacha," fashioned to lend a hand while the work is being carried out, is subject to tumah; a loop "he'asui litlot," fashioned only for hanging the utensil away, is "tahor." Such a loop adds nothing to the utensil's use, and so, however firmly it may be tied on, in the eyes of halachah it is not connected to the keli at all and never picks up its tumah.
The lesson of the mishnah is that attachment in halachah is measured by purpose. Two loops may look identical and be tied on in the same way, yet the one that shares the labor of the utensil is part of it, and the one that merely holds it on a peg is a stranger to it.