In two locations (Kiddushin 81a and Bava Kama 82a), Tosafos mentions the minhag of fasting on the first Monday, Thursday, and following Monday of the months of Cheshvan and Iyar. These fasts, which are also mentioned several times in Shulchan Aruch, are commonly known as BHA”B.
Although most of Klal Yisrael do not observe these fasts, it behooves us to understand the reasons for them so that we can take them to heart and give tzedakah with them in mind.
One reason given by the Elya Rabbah (siman 492, se’if 3) is: They atone for the sin of doing work on Chol HaMoed. The Gemara tells us, “Kol hamvazeh es hamoados, ein lo cheilek l’Olam Habo – All who ignore the moeds have no portion in the World to Come.” Rashi explains that “moed” means Chol HaMoed. We therefore beg forgiveness if we miscalculated during these holy days and did work we weren’t allowed to do.
Another reason can be found in Sefer Matamim (p. 131), Taamei Minhagim (p. 250), and Mateh Moshe (p. 747). They explain that we fast because after Succos and Pesach, the weather changes suddenly, which tends to cause people to get sick. We anticipate this development by fasting and praying for the welfare of Klal Yisrael.
To illustrate how relevant the Gemera’s comment is to contemporary times: Years ago, I was trying to get a hospital room for someone in the emergency room of a New York hospital. The person had already been there for over 30 hours, but the nurse explained to me that there were no ICU or CCU beds available. When asked why the hospital was so congested, she explained that at the change of seasons the hospital is always full because many elderly people just can’t cope with the sudden change in weather. Similarly, a druggist once told me that his briskest business comes at the change in seasons.
The BHA”B fasts after Sukkos are thus an opportune time for rabbanim to remind people to inquire about their elderly parents getting the annual flu shot. Even a “regular” flu – which is a nuisance for younger people – can be, chas v’shalom, fatal to elderly people. Offering a simple preventive flu shot to one’s parents (with the advise of their physician) can be a marvelous fulfillment of kibud av v’eim.
In BHA”B season, the age-old argument on whether to open or close the shul’s windows tends to rear its ugly head. The fact that such disputes occur in shuls is not coincidental. It seems to be a test to see if we have absorbed the divrei mussar and hanhagas tovos that we regularly see in shul. Can we focus more on giving and caring for the other person than taking for ourselves?
Yet another reason for these fasts can be found in the Mordechai on Masechtas Taanis (number 629) and Sefer Chassidim (227). They explain that at the onset of Cheshvan, we begin to expect the yearly rainfall on which our livelihood once depended. And, in the month of Iyar, we are concerned that the fresh crops should not be ruined by devastating natural disasters such as crop jaundice. Hence, these fasts are, in essence, prayers for parnassah, which is definitely a major source of concern in any era.
Finally, Tosafos (on Kiddushin and Bava Kama) explain that we fast because, during Yom Tov, both men and women go to hear a drasha from great sages, and the men were exposed to many women dressed in their Yom Tov finery. To atone for any sinful thoughts they might have had, Chazal enacted a period of fasting and Selichos.
When we learn this Tosafos, we should reflect with fright on how far we’ve deteriorated. In the olden days, the gathering of men and women merely to listen to Torah from the mouths of gedolim prompted a series of fast days. Imagine at how the chachmei Chazal would blanch at the exposure to arayos pervasive among so many today via cinema, television, and digital media.
These fasts remind us how high our standards should really be. (As an aside, we see that it was definitely the practice of women, not just men, to go hear divrei hisorerus.)
In the zechus of our praying for Klal Yisrael’s health and wealth, may we merit these great blessings until the arrival of Moshiach, speedily and in our days.