Not lowering from higher sanctity to lesser sanctity
1. It is forbidden to use klaf which has been processed for sacred purposes for non-sacred purposes (preparation is something significant for this purpose of not changing its use to non-holy), unless one stipulated that he should have the option when he started the processing. It is also forbidden to change its use if he had already started writing on it, even if he had made the stipulation. A get is a non-sacred document.
2. We have already explained in 2:4 how one should process klaf to fit it for sifrei Torah and tefillin and mezuzot. If one had started to write a sefer Torah on it, and the sheet became invalidated, he may not write tefillin or mezuzot on the remainder, because one may not lower from a higher sanctity to a lesser sanctity, and since he had already started to write on it, it’s like when he designated and wrapped (as in para. 6) (see Noda be-Yehuda tenina par. 174, and see Excursus 1 part 19).
3. One may not make a mezuzah from a sefer Torah, or from tefillin. One may not write either tefillin or mezuzot on the margins of a sefer Torah. It is also forbidden to use the margins to repair another sefer Torah, or even to repair that same sefer Torah, unless it is impossible to repair it any other way, in which case one may repair a sefer Torah with klaf taken from its own margins (see the Ḥatam Sofer sec. 279).
4. One may not make tefillin shel rosh over into tefillin shel yad, even if he has two shel roshes and no shel yad; it is even forbidden to take the strap from a shel rosh and use it as a strap for a shel yad. This is because the shel rosh has greater sanctity than the shel yad; more of the name Shaddai is made with the shel rosh. One may, however, make a shel yad over into a shel rosh, if he makes four compartments within. If one had new tefillin which had never been laid, he may make the shel rosh over into a shel yad, as designation alone is not significant here. He does stretch another piece of leather over them, so that they will look like one compartment.
5. If the strap of the shel yad was broken near to the knot, it is forbidden to take the strap out, turn it round, and use the other [less worn out – Maḥatzit ha-Shekel.] end to make the knot, and knotting in the broken end, which used to have the knot in it, below. This is because doing so reduces its sanctity; it used to have the yud in it, and now it is being used for the wrapping (Magen Avraham, and see the Maḥatzit ha-Shekel) – and if the strap was shorter now, he just shouldn’t wrap it so many times around his arm. Even if he discarded the broken part, assuming he had enough left over, he shouldn’t turn it round, but he should make the knot as close to its original location as possible (Peri Megadim).
6. If one designated a particular cloth to be used only for wrapping up tefillin, and he had wrapped tefillin in it once, he may not use it to wrap up money. If he had designated it but never wrapped with it, or had just happened to wrap with it but hadn’t earmarked it specially for wrapping tefillin, he may wrap money in it. If one had made a bag for tefillin, and put tefillin in it, even if he put them in intending to use the bag for something else later, he may not use it for other things. This is also the rule if he had a bag and added anything to it for the purpose of tefillin; if he put tefillin in it intending to use it for something else later, he may not use it for something else (see Magen Avraham, and Excursus 1 sec. 31). If he stipulated from the outset that he should be allowed to use it for anything, he may.
7. Leather which was processed for straps may be used for non-sacred purposes, even if it had already been cut into strap shapes (see Excursus 1, sec. 41)