(א) ערבי פסחים סמוך למנחה. לא יאכל אדם עד שתחשך. ואפילו עני שבישראל לא יאכל עד שיסב. ולא יפחתו לו מארבע כוסות של יין. ואפילו מן התמחוי:
(1) On the eve of Passover [from] close to [the time of] the afternoon offering, no one must eat until nightfall. Even the poorest person in Israel must not eat [on the night of Passover] unless he reclines. And they must give him no fewer than four cups of wine, even [if he receives relief] from the charity plate.
FOUR CUPS: These are parallel to the four languages of redemption which were mentioned regarding the Exodus from Egypt: I will remove you, I will save you, I will redeem you, I will remove you - stated in Parshat Vaera.
FOUR CUPS: Three are parallel to the three cups mentioned [by Pharoah's wine steward to Yosef]. And the fourth is consumed following the Birkat HaMazon.
---> Why does Rashi give two different explanations for why we drink the four cups? It could be related to the question of why women are obligated in the mitzvah...
ואמר ר' יהושע בן לוי נשים חייבות בארבעה כוסות הללו שאף הן היו באותו הנס
And Rabbi Yehoshua ben Levi said: Women are obligated in these four cups of wine at the Passover seder, as they too were included in that miracle of the Exodus, they are therefore obligated to participate in the celebration.
THEY TOO WERE IN THAT MIRACLE:
As it is stated in Sotah 11a, in the merit of the righteous women in that generation we were redeemed [from Egypt]. This is similar to the reading of the Megilla on Purim, in that it was through Esther that we were redeemed; so too regarding the lighting of Chanukah candles...
היו באותו הנס - פי' רשב"ם שעל ידם נגאלו וכן במגילה ע"י אסתר ובחנוכה ע"י יהודית וקשה דאף משמע שאינן עיקר ועוד דבירושלמי גריס שאף הן היו באותו ספק משמע באותה סכנה דלהשמיד להרוג ולאבד והא דאמרינן דפטורות מסוכה אע"ג דאף הן היו באותו הנס כי בסוכות הושבתי התם בעשה דאורייתא אבל בארבעה כוסות דרבנן תיקנו גם לנשים כיון שהיו באותו הנס
THEY TOO WERE IN THE MIRACLE:
Rashbam explained that they [the Jews] were redeemed through them [the women]. And similarly, in the Megilla, through Esther, and in Chanuka, through Judith. And it is difficult, since "even" implies that they aren't the main thing. And also, the version in the Jerusalem Talmud is "even they were in that same uncertainty," implying in that danger of "to destroy, to slay, and to cause to perish" (Esther 3:13). ...[therefore,] regarding the four cups, which is rabbinic, they established it also for women, since they were in that same miracle.
ת"ר הכל חייבין בארבעה כוסות הללו אחד אנשים ואחד נשים ואחד תינוקות א"ר יהודה וכי מה תועלת יש לתינוקות ביין...
The Sages taught in a baraita: All are obligated in these four cups, including men, women, and children. Rabbi Yehuda said: What benefit do children receive from wine? They do not enjoy it...
Sdei Chemed, Maarechet Chametz Umatzah 15:7
I received a letter from R Chaim Berlin, who asked a question regarding the 4 cups - why did Rashi give two different answers in two different places?...He notes that the four languages of redemption correspond to the four decrees Pharoah decreed against them, and the rabbis established the four cups in parallel to these...
What were these four decrees: a) "They embittered their lives", b) "if its a boy, kill them" c) "every son that is born, throw them in the river", d) "Let them gather straw for themselves."...
The second and the third of these decrees were against only the males. But the females only suffered from two of them, the first and the fourth. So why would women be obligated in all four cups of wine?...
Therefore, when Rashi came to the statement of Yehoshua ben Levi regarding "they too were in that miracle", he abandoned his first reason, given in the mishna - namely, the four languages of redemption. He used instead the argument of the word "cup" by Pharoah's steward.
לא יפחתו לו מארבע כוסות - מתוך הלשון משמע קצת שאין נותנין לבניו ולבני ביתו כי אם לעצמו והוא מוציא את כולם בשלו וסברא הוא דמאי שנא ארבע כוסות מקידוש דכל השנה שאחד מוציא את כולם ... אי נמי בבניו ובני ביתו קטנים מיירי שלא הגיעו לחינוך ואין אשתו בכלל ומיהו בגמרא משמע שצריך כל אחד ארבע כוסות דקתני (שם) הכל חייבין בארבע כוסות אחד נשים ואחד תינוקות אמר רבי יהודה מה תועלת לתינוקות ביין משמע דלתנא קמא צריך כוס אף לתינוקות ויש לדחות דחייבין לשמוע ברכת ארבע כוסות קאמר ומשום חינוך ונראה להחמיר ולהצריך ארבע כוסות לכל אחד ...
"And they must give him no fewer than four cups." The language of the Mishna seems to imply that in such a case [of a poor person], we would not give to his children or the members of his household, but rather just to him. And he, in turn, would fulfill the obligation of those in his household through his own drinking.
And this is logical, for what difference is there between the law of the four cups and that of kiddush year round [wherein the person who makes kiddush fulfills the obligations of those at the table]?.... But perhaps the mishna is speaking of a situation wherein his children are minors, who haven't yet reached the age of education, and is excluding his wife?
However, the gemara on 108b implies that every person requires four cups, as it teaches: "everyone is obligated in the four cups, including women and children. Rabbi Yehuda says, why do children need wine?" That gemara indicates that the main author requires even children to drink. One could refute this proof, and say that the author there was requiring everyone [ie the children] to hear the blessing on the four cups, for educational purposes.
It seems we should be stringent and require four cups for everyone....
... וְכָל אֶחָד וְאֶחָד בֵּין אֲנָשִׁים בֵּין נָשִׁים חַיָּב לִשְׁתּוֹת בַּלַּיְלָה הַזֶּה אַרְבָּעָה כּוֹסוֹת שֶׁל יַיִן. אֵין פּוֹחֲתִין לוֹ מֵהֶם. וַאֲפִלּוּ עָנִי הַמִּתְפַּרְנֵס מִן הַצְּדָקָה לֹא יִפְחֲתוּ לוֹ מֵאַרְבָּעָה כּוֹסוֹת ..
...each and every man and woman is obligated to drink on this night four cups of wine. You can't have less than that. And even a poor person who is provided for with tzedakah can't have less than four cups....