The Mitzvah of K’riat Shma

The majority view among rishonim, and certainly later poskim, is that k’riat shma is a mitzvah m’d’orayta, applicable twice a day, daytime and nighttime. Rishonim argue whether this obligation is to be counted as one mitzvah, as understood by the Rambam (Sefer HaMitzvot, aseh 10), or as two obligations, as is the opinion of the Ramban.

The Kessef Mishnah (Hil. Kriat Shma 1:13) questions the apparent lack of symmetry between the nighttime kr’iat shma and the daytime correlate. It emerges from the mishnah, that according to the mainstream opinion, agreed upon in theory by Rabban Gamliel and by the chachomim, is that the nighttime k’riat shma can be recited, m’d’orayta, all night. Why, then, would the daytime k’riat shma be limited to the first quarter of the day? Should they not be parallel? It must be, he concludes, that the concept of “sof zman kriat shma” is a rabbinical one, and that m’d’orayta, the mitzvah can indeed be performed all night.


Most authorities, however, including the Taz (Orach Chaim 58:4) and the Magen Avraham (ibid. 7) disagree with the Kessef Mishnah, noting that purely on grammatical grounds, the wording for the two obligations is different. While “b’shokhbikha” would be translated “while you lie down”, signifying the entire night, ‘b’kumekha” means “when you rise”, not “when you stand”. Hence, only the first part of the day is indicated. (See also Resp. Iggerot Moshe, Orach Chaim IV, 50.)

Further, questions the Magen Avraham, the Kessef Mishnah’s suggestion would appear to be incompatible with the Talmud’s assertion (Berakhot 20b) that kriat shma is a mitzvat aseh sh’haz’man gramma, and thus women are exempt. If, on a biblical level, k’riat shma can be recited all day and all night, it would seem to be not at all time-bound, as it is applicable constantly. Here, as the Sha’agat Aryeh observes, the debate between the Rambam and the Ramban may be relevant. According to the Rambam, if the two recitations are part of one joint mitzvah, then the obligation is indeed constant, if there is no sof zman k’riat shma. However, if the two recitations are seen as two separate obligations, it might be appropriate to use the label mitzvat aseh sh’haz’man gramma; even though one form of the obligation is always applicable, the nighttime recitation cannot be done during the day, and vice versa.

R. Shlomo Wahrman (Sh’erit Yosef, IV, 1) in an essay discussing the general issue of categorizing mitzvot that apply twice a day, suggests that the k’riat shma debate is relevant to another issue. The Shulchan Arukh (Orach Chaim 58:7) records a dispute whether one who misses k'riat shma can "make it up" at the next opportunity (tashlumin). lf the two recitations of shma are understood to be one obligation with two times of fulfillment, such a scenario might be conceivable. If, however, they represent two separate obligations, compensating for one in the time period of the other becomes a less likely possibility.