Rabbi Yitzchak Zilberstein (1934-), in his Hishuqay Hemed commentary on the Talmud (Pesahim 99:2), quotes two earlier sources who try to explain the harsh punishment for eating Matzah on erev Pesah:
חשוקי חמד, פסחים צט:ב: ורבנו מנוח בא ליישב קושיא זו… מצות אכילת מצה אין לו לאכלה אכילה גסה… אבל היכא דאכל מצה ערב הפסח… איכא תרתי: א. אכילה גסה ב. אין היכר באכילתה וכאילו לא אכלה בלילה דמי. ומש”ה מכין אותו מכת מרדות, דכמבטל מצות עשה חשבינן ליה, כיון שאין בה היכר… כתב החק יעקב בשם יש מי שאומר, שהאוכל מצה בערב פסח הוא מהתורה. מדכתיב בערב תאכלו מצות ולא ביום
Rabennu Manoah answers this question… The Mitzvah of eating matzah is not fulfilled with crude eating (meaning that one is already full and he forces himself to eat the Matzah)… if one eats Matzah on Erev Pesah there are two problems: 1. Crude eating. 2. There is no sign when he eats Matzah at night that he is doing it for the Mitzvah. That is why he is lashed because it is as if he did not fulfil the Mitzvah.
The Hok Yaakov wrote in the name of an anonymous author, the eating Matzah on Erev Pesah is a biblical prohibition, since the Torah says “you shall eat Matzah at night” [and we can deduce from it] at night and not during the day.
Let us analyze the arguments presented here. Rabbenu Manoah claims that if one eats Matzah on Erev Pesah, he will be full at night. According to that, one should get lashes if he ate too much of any type of food. Rabbenu Manoah probably knew that this argument is insufficient, and therefore added the second reason. But for that argument to be valid, the prohibition should have been very specific: if one eats Matzah on Erev Pesah in a way which will render the Seder insignificant, he will be punished. How can we say that if someone grabbed a piece of Matzah on Erev Pesah, spread some jam on it, and) if he is Sephardic) said Birkat Mezonot and ate it, that this makes the Seder experience null and void?
Furthermore, while the Torah does say that if one willfully did not do the Pesah sacrifice he will be punished, that punishment is not administered by humans. If the transgression is indeed failing to eat Matzah on the Seder night, and if Matzah is equated to Korban Pesah, the Talmudic statement, and Maimonides’ ruling, should have read:
כל האוכל מצה בערב פסח מת בהכרת, שלא קיים מצות אכילת מצה בלילי פסחים
If one eats Matzah on Erev Pesah he will die at a young age, because he failed to observe the Mitzvah of eating Matzah on Seder night.
But that is not what is written, so the second argument of Rabbenu Manoah is also not convincing.
Now the argument of Hok Yaakov that not eating matzah on Erev Pesah is biblical prohibition because of the inference from the text is very strange, because if we apply this logic to similar biblical commandments, we will find many new and unheard-of prohibitions, such as starting Kippur early. How so? The Torah says (Lev. 23:32):מֵעֶ֣רֶב עַד־עֶ֔רֶב תִּשְׁבְּת֖וּ שַׁבַּתְּכֶֽם – You shall cease [from working and eating] from the night to the following night. By the logic of Hok Yaakov, that means that you cannot cease from on the eve of Kippur, and that the few minutes that we add before Kippur are actually the last sin before the fast starts.
No one suggests that, obviously, and that renders the argument of Hok Yaakov invalid.
Rabbi Yisakhar Tamar (1896-1982) in his Alay Tamar commentary on the Yerushalmi (Nazir 4:1), is perplexed by the illogical disparity between the punishment administered for transgressing prohibitions of different levels:
והנה הלכה זו תמוה מאד דבמלקות תורה של חייבי לאוין מלקין אותו ארבעים ובאיסור דרבנן עד שתצא נפשו
This Halakha is very strange: if one transgressed a biblical prohibition, he only gets 40 [i.e. 39] lashes, but if he transgresses a rabbinical one, he is lashed to death?
He answers his question:
ונראה ששני דינים שונה הברייתא במכות מרדות, א) כשעבר על איסור דרבנן חובטים אתו עד שיקבל עליו שלא לזלזל יותר באיסור דרבנן, וכמו… לאכול מצה בערב פסח, שאז חובטים אותו עד שיקבל… ואם הוא חצוף ועומד ברשעו… חובטים יותר אבל רק עד ל”ט מלקות ולא יותר… ב) ההלכה השניה במכת מרדות שמסרב לקיים המצוה היא עד שתצא נפשו, וכגון שאומרים לו עשה סוכה ואינו עושה
It seems that there are two different laws in the Barayta regarding lashes of rebellion: 1. When one transgresses a rabbinical prohibition he is lashed until he accepts to not disregard again rabbinical prohibitions, such as… eating Matzah on Erev Pesah, in which case he is lashed until agreeing… if he is stiff-necked… he gets more lashes but no more then 39… 2. The second halakha with lashes of rebellion is when he refuses to observe the Mitzvah, in which case he is lashed to death, as when being told to build a Sukkah [and dwell in it] and he refuses.
Putting aside the problematic issue of lashes in general, Rabbi Tamar’s argument does not answer the question about Maimonides’ ruling, but he claims it does. I would appreciate the readers’ in deciphering his statement.
But there is a simpler solution to the words of Maimonides, which Rabbi Tamar also presents:
גירסא זו תמוה, ועיין בחומש תו”ש במלואים סוף סימן ל”א שכתב שבדפוסים הראשונים ובארבע כתבי יד שלפניו ליתא כלל המילים עד שתצא נפשו, רק בדפוס וינציא של”ד הוכנסו שם בראשונה
This version is strange, and see Humash Torah Shelema (appendix, 31) who wrote that in the early printed editions and the four manuscripts he had the words “until he dies” are not written, and were inserted for the first time in the 1574 Venice edition.
This view is supported by Rabbi Israel Eisenstein (1837-1905) who writes in Amuday Esh (1):
עמודי אש סימן א: נראה דהרדב”ז והרב דוד עראמה לא היו גורסים כלל גבי אוכל מצה בערב פסח דמכין אותו עד שתצא נפשו, וכמו שמבואר במעשה רוקח שם דיש גירסאות שאין כתוב זה ברמב”ם. וכן כתב בשו”ת מהרלנ”ח באגרת הסמיכה
It seems that Rabbi David ben Zimrah and Rabbi David Arameh did not accept the version “until he dies” as the Maashe Roqeah explains that these words do not appear in some versions of Maimonides, and it is also the opinion of Rabbi Levi ben Haviv in his letter on the Semikha.
Finally, in the most accurate edition of Mishneh Torah currently available, the Frankel edition, the words do appear, but the editor commented that:
ברוב כתבי יד וברוב דפוסים ישנים ליתא
These words do not appear in most manuscripts and most early print editions.
So, we can sigh a sigh of relief and conclude that eating Matzah on Erev Pesah is not a capital offense. Still, it is worrisome to know that a mistake of a scribe who added three words of memory to a manuscript of Maimonides he was copying, led many Halakhic authorities to believe that one might be killed for eating Matzah on Erev Pesah, and to invent seemingly convincing arguments to prove it.
And this is just the beginning. Now that we clarified what Maimonides really says, we still have to understand why the rabbis forbade it in the first place and why they made the strange analogy to semi-forbidden relationships.