INTRODUCTION: The Halakhot of K’riat Sh’ma, comprising one Mitzvat Aseh, namely to read K’riat Sh’ma twice a day. The explanation of this Mitzva is in these chapters:
Q1: Why does Rambam reckon K’riat Sh’ma as only one Mitzva, even though there are two distinct times for it?
YF (Yitzchok Fishman ): It is only one Mitzva because both times are derived from the same place.
YE (Yitz Etshalom): According to that reasoning, Rambam should reckon hand-Tefillin and head-Tefillin as one Mitzva (he doesn’t) – since they are derived from the same source.
The question becomes stronger when we note that several Rishonim (Sa’adia, Ramban) reckoned K’riat Sh’ma as two separate Mitzvot. Ramban’s argument is as follows: Since it is possible to fulfill one (e.g. evening Sh’ma) without fulfilling the other (morning Sh’ma), the two are separate Mitzvot. Rambam himself uses this argument to explain why the four species taken during Sukkot are one Mitzva: Since all four are necessary components in the fulfillment of the Mitzva, it should be considered one Mitzva (Sefer HaMitzvot, Shoresh 11). Following that reasoning, Rambam should reckon K’riat Sh’ma as two separate Mitzvot.
In the Introductory Shiur, we discussed various possible “Kiyyumim” (Mitzvot which are fulfilled) in K’riat Sh’ma – Talmud Torah (Tosafot, RAAVAN), “Yichud Hashem” – declaring God’s unity (Sa’adia), “Kabbalat ‘Ol Malkhut Shamayim” – acceptance of God’s authority (Yere’im). We don’t yet know which of these, if any, are considered by Rambam to be woven into the fabric of K’riat Sh’ma.
Talmud Torah: It is possible to understand K’riat Sh’ma as the two daily “flash points” of ongoing Talmud Torah. This notion may be found in the Gemara in Menahot (99b): This Gemara follows a discussion of R. Yose’s opinion regarding the consistent presence of “Lechem haPanim” – showbread – in the Kodesh. The Torah commands us to have the Lechem haPanim “in front of Me *Tamid*”. The first opinion details how two Kohanim would stand and remove the old Lechem haPanim on Shabbat and, as two others would be sliding the new Lechem on the Table, they would slide it off – that the Lechem should be there “Tamid”. R. Yose argued that even if the old Lechem was removed on Shabbat morning and the new one was placed at the end of Shabbat, it was still considered “Tamid” – consistently present. Based on this reasoning, the Gemara contends that a person could be considered to be learning constantly – i.e. “day and night” – with minimal study by day and by night…)
“R. Yohanan said in the name of R. Shim’on b. Yohai: Even if a person only reads Keri’at Sh’ma in the morning and the evening, he has fulfilled ‘This book of the Torah shall not depart out of your mouth'”.
If K’riat Sh’ma is the daily/nightly anchor of Talmud Torah, it may certainly be considered one Mitzva – for we don’t reckon daytime learning and nighttime learning separately, as they are ongoing.
Yichud Hashem/Kabbalat Ol: There is room to argue that Rambam considers K’riat Sh’ma as a Kiyyum of Yichud Hashem. In Sefer haMitzvot, Mitzvat Aseh #2, he uses the verse of Shma Yisra’el as the source for the Mitzva of declaring God’s Unity – and he refers to this declaration as “Acceptance of the Authority of God”. Since Yichud Hashem is a Mitzva which is not bound by time, and K’riat Sh’ma is the twice-daily declaration of this constant awareness/Mitzva, it stands to reason that it is one Mitzva: Declaring God’s unity twice a day.
Rambam may provide an answer for us; in Sefer haMitzvot, Shoresh 11, he explains that even though the blue and white threads of Tzitzit may be independently worn (the absence of one does not invalidate the other) – “Tzitzit” is still considered one Mitzva “…when it is one matter, for the aim of Tzitzit is ‘In order that you remember [the Mitzvot]’, therefore, the whole matter which creates the commemoration is counted as one…”
In the same way, since the purpose of both daytime and nighttime K’riat Sh’ma is, in any case, one goal (whatever the aim – study, declaring God’s Unity – it is the same goal during the day and at night) – we may consider it one Mitzva.
Q2: Why does he term it “twice a day”, as opposed to “at night and during the day”?
YE: Following the answer above, the essential Mitzva is not rooted in its specific times, rather in the “twice a day” – two points during the 24-hour period to fulfill this Mitzva and all that follows from that.
Rambam, Copyright (c) 1999 Project Genesis, Inc.