We are commanded in the fourth of the Aseret Ha’diberot (Shemot 20:8), “Zachor Et Yom Ha’Shabbat Le’kadesho” – “Remember the day of Shabbat, to regard it as sacred.” The Gemara understood the command of “Zachor” (“Remember”) as requiring not just cognitively remembering Shabbat, but verbally declaring its unique stature of sanctity both when it begins and when it ends. This command, then, is the source of the obligation to recite Kiddush when Shabbat begins and Habdala when Shabbat ends.
In explaining the reason behind this command, the Sefer Ha’hinuch returns to the principle which he had previously developed, that our hearts and minds are impacted by our actions. He writes that the Torah commanded us to declare the sanctity of Shabbat because this will enhance our appreciation of the great importance of this day. The observance of Shabbat commemorates G-d’s having created the world in six days, thereby affirming the belief in a Creator, that G-d brought the entire universe into existence. The singular importance of this belief necessitates not only observing Shabbat, but making a verbal proclamation when it begins and ends to emphasize for ourselves the significance of this occasion. For this same reason, the Sefer Ha’hinuch explains, our Sages instituted that these recitations should be made over a cup of wine – because this ensures that the recitation will leave a stronger impression. Wine is a unique beverage, as it satiates and also brings joy, and so we recite Kiddush specifically over a cup of wine to make this recitation more dramatic and impactful. The Sefer Ha’hinuch notes the Gemara’s ruling that if one prefers bread over wine, he should recite Kiddush over bread, instead of wine. The reason, the Sefer Ha’hinuch explains, is because for such a person, reciting Kiddush over bread will be more impactful than reciting Kiddush over wine. (Habdala, however, cannot be recited over bread, and the Sefer Ha’hinuch explains that at the end of Shabbat, most people do not have much of an appetite, as they had enjoyed the robust Shabbat meals, and therefore reciting Habdala over wine is more impactful than reciting it over bread.)
The Sefer Ha’hinuch applies this theory to explain several Halachot pertaining to Kiddush, such as the requirement to recite Kiddush and Habdala over a Rebi’it of wine, rinsing the cup before Kiddush, and the prohibition against eating or drinking before Kiddush or Habdala. These Halachot are all geared towards impressing upon us the unique importance of Shabbat.
Although this Misva applies only at particular times, and women are generally exempt from Misvot Aseh She’ha’zman Gerama (timebound affirmative commands), women are included in the Misva of Kiddush. The Gemara in Masechet Berachot establishes that the obligation of “Zachor Et Yom Ha’Shabbat” is linked to the command of “Shamor Et Yom Ha’Shabbat,” which forbids performing Melacha (forbidden activity) on Shabbat. Thus, since women are bound by the prohibitions of Shabbat (just as they are bound by all Torah prohibitions), they are similarly bound by the command of Kiddush.
The Kiddush we recite on Shabbat day – commonly referred to as “Kiddusha Rabba” – was instituted by the Sages, and is not included in the Torah obligation. The Sefer Ha’hinuch explains that the Sages instituted this recitation in order to distinguish the Shabbat meal from our weekday meals. The Rambam was of the opinion that one should drink wine at Se’uda Shelishit, as well. Although this is not generally practiced, it is preferable to include wine at Se’uda Shelishit. I recall once eating Se’uda Shelishit together with Hacham Shlomo Amar Shelit”a, Sephardic Chief Rabbi of Jerusalem, and he made a point of requesting wine so he could satisfy this opinion of the Rambam.
A number of Poskim addressed the question of why we do not fulfill the Torah obligation of Kiddush by reciting Arbit on Friday night. After all, the Sefer Ha’hinuch defines the Kiddush obligation as requiring verbally declaring the special quality and greatness of Shabbat, which is precisely what we do in the text of the Amida prayer recited on Friday night. Seemingly, then, this recitation should suffice to fulfill the Torah obligation of Kiddush.
Four different reasons have been given to explain why reciting the Friday night Amida prayer does not suffice to fulfill this Misva.
The Minhat Hinuch explains based on the famous rule of “Misvot Serichot Kavana” – that one fulfills a Misva only if he has mind when performing the action that he intends to fulfill the obligation. Quite obviously, when we recite Arbit on Friday night, we have no intention to fulfill the Misva of Kiddush, and so this recitation does not satisfy the Kiddush obligation.
The Minhat Hinuch then goes even further, claiming that even according to the view that “Misvot En Serichot Kavana” – one fulfills a Misva even if he does not have the Misva in mind when performing the action – we do not fulfill the Misva of Kiddush through the recitation of Arbit. According to this view, one can fulfill a Misva even if he had no specific intention for the Misva, but even this view agrees that one cannot fulfill the Misva if he has a different Misva in mind when performing the action. When we recite Arbit on Friday night, we do so to fulfill the Misva of prayer, and therefore, since we specifically have a different Misva in mind, all views agree that we do not at the same time fulfill the Misva of Kiddush.
Others explain based on the Gemara’s remark that we must make mention of the Exodus from Egypt as part of our recitation of Kiddush. Since the text of the Friday night Amida makes no mention of the Exodus, it does not suffice to fulfill the obligation of Kiddush.
Finally, some Rabbis asserted that once the Sages instituted that the Misva of Kiddush should be fulfilled over a cup of wine, this is how the Misva must be fulfilled, and we cannot fulfill this Misva – even on the level of Torah law – in any other way.