April 4, 2017
Beis Moshiach in #1064, Halacha 2 Go

Selected Halachos from the “One Minute Halacha” project

By HaRav Yosef Yeshaya Braun, Shlita,
Mara D’asra and member of the Badatz of Crown Heights


There are three differing opinions among poskim on the subject of koshering glass, namely: 

Glass doesn’t absorb, and therefore there is no need to kasher a glass utensil. It only has to be washed and wiped clean.

The opinion on the opposite end of the spectrum is that glass does absorb, and that this absorption is irreversible and cannot be kashered

The middle-ground opinion is that glass, like most other materials, needs to be kashered if it becomes treif, and can in fact be kashered.

The Sephardic custom is to be lenient and follow the first view. Ashkenazim, although they concur with the third view in principle, are stringent in practice and do not kasher glass. Some argue that this stringency only applies to Pesach glassware—that is to say, we never rely on koshering glass to remove chametz—but others are stringent all year round.


During the era of the Beis HaMikdash, Chazal instituted a prohibition against any Jewish person performing work from midday on Erev Pesach—the hours in which the korban Pesach was offered. This Rabbinical prohibition was not removed even after the destruction of the Beis HaMikdash and the discontinuation of the korban Pesach.

All activities that may be performed during chol ha’moed—such as a matter that will be lost if left unattended, or something that is necessary for the days of chol ha’mo’ed and is done non-professionally, not as a worker trained in that field—may certainly be performed on Erev Pesach afternoon.

It is only true work that may not be performed, such as crafting a new utensil or sewing new garments. By contrast, one may repair something that has been slightly damaged and is needed at present. Similarly, one may sew and repair clothing that has been slightly torn or damaged and is needed for yom tov. Work of this kind may be performed in a professional manner for oneself, or for someone else but without payment.

Professional writing is considered a true form of work and is not permitted even for a mitzvah.


The term k’zayis is frequently found in Torah sources. A k’zayis is the volume of an average-sized olive. However, there is a difference of opinion amongst early authorities as to the volume of an average-sized olive. Many Rishonim maintain that a k’zayis is approximately the equivalent of half an average-sized egg (without its shell). Another opinion is that a k’zayis is slightly less than a third of an egg (with its shell).

Regarding a Torah rule, such as eating a k’zayis of matza on the first night of Pesach, we must be stringent and go by the larger shiur; regarding the amount of maror to be eaten, which is a Rabbinic ruling, we can be lenient, if necessary. At times the larger shiur is a leniency: For example, regarding the halacha of destroying any chametz over a k’zayis found in our possession on Pesach which is a Biblical law, we must be stringent and deem the smaller shiur k’zayis as the k’zayis. (According to Rabbinic law, we must destroy even chametz which is under a k’zayis.)

Before making a bracha acharonah, an after-blessing—which is required only after eating a k’zayis—one should be sure to eat at least the equivalent in volume of half an average egg in order to avoid the possibility of saying a bracha in vain. One should avoid the equivocal zone: either eat less than the smaller shiur k’zayis and not make a bracha acharonah, or eat more than the larger shiur k’zayis so that a bracha acharonah can be said—in compliance with all opinions.


The lav (Torah prohibition), “Lo yilbash gever simlas isha” (a man may not dress in a woman’s garment) prohibits many types of adornments and beauty enhancements normally practiced by women; in this vein the Talmud Yerushalmi states that men gazing in the mirror is also a violation of lo yilbash.

However, the Yerushalmi continues, there are exceptions to this precept, such as those who are krovim l’malchus (involved with the government)—they may look in the mirror to maintain the impeccable standards of dress befitting their position. Poskim maintain that there are also a range of non-glamour related activities where mirror use by men is sanctioned: to examine the body for health purposes, to avoid nicking the scalp while taking a haircut, to properly position t’fillin shel rosh (head t’fillin), and for checking for food stains or dandruff on the person or clothing to present a well-groomed appearance. Halachic authorities add that even absent some sullying substance, a man may glance in the mirror to simply straighten his clothing to look presentable.

Later authorities qualify that since in the current age mirrors are no longer considered gender-specific, the above restrictions are relaxed and mirrors may be used for a range of purposes by men as well. Other authorities nevertheless maintain that chaverim (“colleagues”; i.e., Torah scholars) refrain from gazing in mirrors indiscriminately and maintain the standards of previous generations. There are also kabbalistic motives for men curbing their mirror use, as it states in the Zohar concerning ruchos ra’os (evil spirits) unleashed by males who use mirrors, including a memunah (appointed [angel]) called Mar’eh (“mirror”) whose negative energies are thus fortified. Obviously, this warning does not apply to utilizing the mirror when sanctioned by halacha—those activities outlined by the Yerushalmi and earlier poskim.

The established practice is that mirror-use by men is only restricted when it is li’hisgaos (for vanity)—but in other circumstances and when in the range of acceptable halachic practice, or otherwise l’sheim Shamayim (for the sake of Heaven), it is acceptable. Some latter-day poskim mention that in current times, when a Torah lifestyle has become more marginalized, it is even more important than in previous generations for talmidei chachamim to be well-groomed and neatly dressed in order to make a positive impression; using a mirror for this purpose is proper since it enhances respect for Torah in the larger community.


One of the principles of our faith is to believe in Moshiach—and not only to believe in Moshiach, but to anticipate his coming every single day. It is a fundamental tenet of Yiddishkait, and there are numerous references to Moshiach’s coming in the Torah. Indeed, we pray many times a day for his coming.

One of the first questions asked of each departed soul by the beis din shel malah (Heavenly tribunal) is: “Tzipisa l’yeshuah?” (“Have you yearned for the Redemption?”) Some poskim say that believing that Hashem will redeem us through the coming of Moshiach is actually part of the principle of Anochi Hashem Elokecha, believing in Hashem. A person who does not do so is denying a basic tenet of Yiddishkait; therefore, it is crucial to make everyone aware of this basic principle of our faith.

Part of believing in and awaiting Moshiach is not to make any pre-conditions for his coming: for example, we may not say that because Eliyahu HaNavi has not come, therefore Moshiach cannot come yet. Nor may we set a keitz (a specific time) by when Moshiach should come, but rather we should constantly be anticipating his arrival. It is a halacha to yearn and pray for Moshiach every time we think or talk about him.

“One Minute Halacha” is a succinct daily presentation on practical Halacha in video, audio, and text formats, and can be accessed by phone at 718.989.9599, by email,, or by WhatsApp 347.456.5665.


Article originally appeared on Beis Moshiach Magazine (
See website for complete article licensing information.