Today is the Tenth of Tevet, the day when the king of Babylon besieged Jerusalem with the intention of destroying it, as the verse (Yechezkel 24) states, “And the word of Hashem was unto me in the ninth year in the tenth month on the tenth of the month saying: ‘Son of man! Write for yourself the name of the day the very essence of this day; on the very essence of this day, the king of Babylon invested Jerusalem.’”
It is for this reason that we fast on the Tenth of Tevet in order to humble our hearts and repent whole-heartedly while beseeching Hashem to have pity in us and redeem us for all eternity. Indeed, the Rambam writes that the reason why the Jewish nation fasts on days when calamities befell the Jewish nation is in order to arouse one’s heart and to open the pathways of repentance. This day will serve as a commemoration of our wicked deeds as well as the wicked deeds of our forefathers who have acted as we are acting now which in turn caused this suffering to befall them and subsequently us as well. By remembering these things, this will cause us to better our ways, as the verse states, “And they shall confess their sins and the sins of their fathers.”
This public fast day was enacted by our Sages and it is forbidden to eat or drink on this day; however, the prohibition to eat on this day is not Torah law, rather, it is a rabbinic decree.
Let is now discuss a situation where one forgets that it is a fast day and recites a blessing on a certain food and immediately before placing it in his mouth, one remembers on his own or others remind this individual that it is a fast day and eating is forbidden. How should one proceed?
The Responsa Halachot Ketanot discusses such a scenario and he writes that one should taste a small amount of the food or beverage so that one’s blessing does not become a blessing in vain. Hagaon Harav Yonah Navon, teacher of Maran Ha’Chida, rules likewise in his Sefer Nechpa Ba’Kessef since the sin of reciting a blessing in vain is a grave sin and according to the Rambam, this is an actual Torah prohibition whereas tasting some food on a public fast day is merely a rabbinic prohibition. Therefore, the individual should be instructed to taste some of the food so that his blessing will not have been in vain.
Maran Rabbeinu Ovadia Yosef zt”l deals with this issue in several of his works, especially in his Responsa Yabia Omer, Volume 2, Yoreh De’ah, Chapter 5 where he rebuffs all of the claims against the opinion of the Nechpa Ba’Kessef and concludes that his ruling is the correct one and thus, one should taste a tiny amount of the food one recited a blessing on and then continue fasting until the fast’s conclusion.
Elsewhere (Responsa Yechave Da’at, Volume 4, Chapter 41) Maran zt”l writes that a similar incident once occurred to Hagaon Harav Avraham Elkal’ai, as he himself records in his Sefer Zechor Le’Avraham:
“Once, on a winter day, after I had eaten meat only four hours ago, I had forgotten about this and recited a blessing on cheese. As I placed it in my mouth, I immediately remembered that I had eaten meat.” He writes that halachically, one should swallow a small amount of the cheese so that one’s blessing is not in vain. Although Maran Ha’Shulchan Aruch rules that one must wait six hours after eating meat before eating cheese, nevertheless, since there are several opinions among the Rishonim regarding this matter in addition to the fact that this is a rabbinic prohibition (and not a Torah prohibition), everyone would agree that one should taste a bit so that one’s blessing is not in vain.
Maran zt”l defends his opinion based on several sources and proofs and rules that the same applies to one who mistakenly recites a blessing on food on a public fast day in that if one already recited a blessing on a food on a public fast day, one should taste a small amount of the food and then continue to complete the fast until nightfall.
