Threading a shoelace

Hi,

One may not thread a shoelace into a shoe on Shabbat, unless the lace was already in use for that shoe. The reason is that designating the lace to remain in this shoe is an act of rendering the shoe functional.

Based on this logic, it would appear that one could insert a temporary lace, where it was clear that the lace would not remain there - such as where the colour was wrong for the shoe, or where the lace was borrowed from someone else. However, Rabbi Shlomo Zalman Auerbach ruled not to distinguish among cases in this matter.

(Rivivot Ephraim 1:243)

Have a great day,
Mordechai

Hearing aids on Shabbat

Hi,

We are lenient regarding use of a hearing aid on Shabbat. This is different from use of a microphone:

With a microphone we are concerned that people normally connect it only when they need it, so that people will assume it was turned on during Shabbat, but that concern only applies regarding items which make noise, calling themselves to the attention of the public.

The concern of "don't use it lest you adjust it" which we express regarding microphones also applies regarding hearing aids, but a) that is a rabbinic decree and so it may not apply to the uncommon case of a hearing aid (for rabbinic decrees were created only for common cases), and b) the hearing aid involves great need, such as to hear an oncoming car. However, one should do something to prevent actual adjusting.

As far as the concern that one activates a microphone to create a new voice when he speaks, and so one is finishing its construction (makeh b'patish) or actually building it (boneh), neither of these is clear-cut, and this is a case of great need, as we have explained. [There is more here in Rav Moshe's discussion.]

As far as the concern that one's voice causes the electrical current to rise or fall, the prohibition involved is not clear, and this is a case of great need.

Further, sometimes the hearing aid does not pick up the sound, and so its activation is not a guaranteed result of one's action.

Further, if one speaks to people in general, and not only to the person with the hearing aid, then one does not intend to activate it. Indeed, ideally one should avoid speaking to him personally, if at all possible.

(Igrot Moshe Orach Chaim 4:85)

Have a great day,
Mordechai

Microphones on Shabbat

Hi,

There are four main reasons to prohibit speaking into a classic microphone on Shabbat:

Causing a microphone to broadcast a sound via its reaction to one's voice may involve completing the microphone's functionality or building it, which would be biblically prohibited;

Causing the electrical current to rise and fall may involve biblical prohibitions, even though the circuit remains "on" throughout the operation of the microphone;

We may not engage in activities which appear to be prohibited ("marit ayin"), and since microphones are normally turned on only when needed, listeners may not realize that this sound system was turned on before Shabbat;

If the sound system were to malfunction, one might forget it is Shabbat and adjust it.

(Rav Moshe Feinstein, Igrot Moshe Orach Chaim 4:84)

Have a great day,
Mordechai

Opening a milk container on Shabbat

Hi,

Regarding containers as are commonly used for milk, which have spouts that are glued closed, so that one needs to separate them and draw out a spout which had been folded inward: One may not open these on Shabbat, for that is a form of completing construction of the container, making it usable.

Some do point out that the spout was already open at one point, before it was glued shut, but this is irrelevant; the gluing erased that original opening.

(Rav Moshe Feinstein, Igrot Moshe Orach Chaim 4:78)

Have a great day,
Mordechai