Rabbi Yonason Sacks
The Arba Kosos
Although the Talmud Bavli addresses the halachos of the arba kosos, it never cites a source for the mitzvah (see the Ran, 19a in the Rif s.v. "Me'arba'ah," who asserts that the arba kosos were instituted so that each of the four sections of the Seder would be recited over wine). The Talmud Yerushalmi (Pesachim 10:1), however, cites numerous possible sources:
R' Yochanan said in the name of R' Benaya: [the four cups] correspond to the four expressions of redemption… R' Yehoshua ben Levi said: they correspond to the four cups of [the butler of] Pharaoh's dream... R' Levi said: they correspond to the four kingdoms. The Rabbis say: they correspond to the four cups of affliction which HaKadosh Baruch Hu will eventually serve to the nations of the world…And corresponding to them, HaKadosh Baruch Hu will serve Bnei Yisrael four cups of comfort.
The Medrash Rabba (Shemos 6:4) states that the four expressions of redemption mentioned by R' Benaya in turn correspond to the four decrees which Pharaoh wrought against Bnei Yisrael. Moreover, the Meiri (Pesachim 99b s.v. "V'lo") adds that each of the four expressions signifies a redemption within itself: "V'hotzeisi" refers to the redemption from the physical servitude of Mitzrayim. "V'hitzalti" refers to redemption from the ‘normal' subjugations of kingdoms, such as taxes and tributes to the king. "V'ga'alti" teaches that HaKadosh Baruch Hu will bring about the complete domination of the Jewish people over their foes. And "V'lakachti" alludes to the giving of the Torah, which is the "tachlis hakol - the ultimate purpose of everything."
Interestingly, Rashi seems to acknowledge multiple sources for the mitzvah of arba kosos. In the opening mishnah of perek Arvei Pesachim (Pesachim 99b), Rashi cites the four expressions of redemption as the definitive source for the arba kosos. Later in the perek, however (Pesachim 108a), when explaining R' Yehoshua ben Levi's ruling that women are obligated to drink the arba kosos, Rashi cites the dream of Pharaoh's butler. These differing sources pose some uncertainty regarding Rashi's own opinion. HaGaon R' Betzalel HaCohen (Haghos Mar'eh Kohen Pesachim 108a) explains Rashi's sources contextually: because R' Yehoshua ben Levi himself issued the ruling on Pesachim 108a, Rashi cites R' Yehoshua ben Levi's own opinion in the Talmud Yerushalmi regarding the dream of Pharaoh's butler. On the mishnah, however, Rashi cites the four expressions of redemption because only they can adequately account for the mishnah's subsequent ruling that "even an indigent pauper must purchase (or receive) four cups of wine on Seder night." The four expressions of redemption highlight the fact that the mitzvah of arba kosos constitutes "pirsumei nisah" - publicizing a miracle. The critical value of pirsumei nisah overrides fiscal concerns, obligating even the most penurious members of Klal Yisrael to fulfill the mitzvah. R' HaCohen infers from Rashi's citation of alternate sources that the opinions in the Yerushalmi are not necessarily in disagreement. Rather, each source adds an additional dimension to the nature and importance of the mitzvah.
As noted, the Talmud Bavli conspicuously omits any source for the arba kosos. Perhaps this omission may relate to a deeper understanding of the conceptual nature of the arba kosos. R' Chaim Soloveitchik (cited in Chidushei HaGriz Hilchos Chametz U'Matzah 7:9) observed that, objectively, the arba kosos may be said to consist of two components: "recital" of the various parts of the Seder over a cup of wine, and "drinking" of the wine itself. While all opinions agree that both "recital" and "drinking" constitute critical components of the mitzvah, the rishonim seem to debate which one of these two components constitutes the essence of the mitzvah, and which one serves a more technical, ancillary role. This analysis may account for a number of fundamental disputes between the rishonim, and may shed light on the Bavli's omission of any source for the arba kosos.
One area in which this investigation may express itself pertains to the question of whether one must actually drink in order to fulfill the mitzvah of arba kosos. Tosafos (Pesachim 99b, s.v. "Lo") argues that the mitzvah of arba kosos may be fulfilled through the vehicle of "shomeiah k'oneh," which renders listening tantamount to speech. By simply listening to the recital of the bracha, one fulfills the obligation, even without drinking any wine. In this respect, Tosafos analogizes the mitzvah of arba kosos to the mitzvah of Kiddush throughout the year, which also does not necessitate actual drinking on the part of the listener. The Rambam (Hilchos Chametz U'Matzah 7:7), however, disagrees. In order to fulfill one's obligation of arba kosos, one must actually drink four cups of wine. Unlike Kiddush of the rest of the year, mere listening is insufficient.
R' Yitzchak Zev Soloveitchik explains that this machlokes may reflect a fundamental difference of opinion regarding the nature of arba kosos. Tosafos, who accept the mechanism of "shomeia k'oneh" in lieu of actual drinking, view "recital" as the main component of the mitzvah. The presence of the cup serves to embellish and to confer significance to the verbal elements of the Seder. Drinking itself is merely a technical requirement which follows the recital. As such, one could theoretically fulfill one's obligation without drinking any wine at all. The Rambam, however, perceives the actual drinking of the wine as the definition of the mitzvah. Hence, although "shomeia k'oneh" can compensate for lack of speech, it cannot redress the lack of drinking by the listener, and is thus an insufficient means for fulfilling one's obligation
Tosafos' opinion, that the primary component of the arba kosos exists in the "recital," not the actual drinking, is also evinced in their comments to Maseches Succah (38a s.v. "mi"). Tosafos note that although women are generally exempt from the positive time-bound mitzvah of Hallel, women are nonetheless obligated to recite the Hallel of Seder night. Tosafos prove this obligation from the fact that women are obligated in arba kosos: if the role of arba kosos, Tosafos reason, is to serve as an "enhancer," conferring greater significance to the recital of Hallel and Hagaddah, it follows that anyone obligated in the arba kosos must certainly be obligated in the recital of Hallel and Haggadah itself. Tosafos' reasoning presupposes the assumption that the essential component of the arba kosos is to enhance the recital of the Hallel and Haggadah, not the actual drinking itself.
This machlokes may also account for the necessary shiur (requisite amount) of arba kosos. The Rambam (Hilchos Chametz U'Matzah 7:9) rules that one must drink a "rov kos" - the majority of a cup - in order to fulfill the mitzvah. The Ramban (quoted in Beis Yosef O.C. 472:9) concurs, adding that even if the volume of the cup is extremely large, one must drink the majority of that particular cup. This shiur exceeds the regular "m'lo lugmav," or cheek full, necessary for Kiddush throughout the year. The uniqueness of this shiur may also relate to the nature of arba kosos. If the essence of arba kosos lies in the "recital," enhancing the portions of the Seder which are recited over wine, arba kosos should be no different than Kiddush, and a cheek full should suffice. If, however, the emphasis of arba kosos lies in the actual drinking of the wine, one could well envision a new shiur arba kosos of "rov kos" (the Talmudic principle of "rubo k'kulo" equates drinking the majority of the cup with drinking the entire cup).
A further ramification of this analysis may emerge regarding whether or not the wine of the arba kosos must be diluted. In Talmudic times, wine was sold in a strong, undiluted form, which only attained optimal drinking taste after being diluted with water. According to Tosafos, who perceive the essence of the mitzvah in the recital as opposed to the actual drinking, dilution of the wine is not critical (although it is certainly commendable). According to the Rambam's opinion, however, the drinking itself constitutes the central aspect of the mitzvah. As such, perhaps greater importance is placed on the details of the drinking, and diluted wine would be essential to fully fulfill the mitzvah.
Finally, this analysis may also account for the Bavli's omission of any source for the mitzvah of arba kosos. If the drinking of the wine itself constituted the central component of the mitzvah, a source should seemingly be necessary to teach the new halacha. If, however, the cups serve merely to enhance the recital of the Hallel and Hagaddah of the Seder, perhaps the mitzvah of arba kosos is subsumed under the larger mitzvah of Hallel and Haggadah. Because arba kosos does not constitute an independent mitzvah, no independent source is necessary.