Lashon Tzivui vs. Lashon Sippur — Imperative Form vs. Narrative Form
וּלְעָבְדוֹ בְּכָל לְבַבְכֶם
And to serve Him with all of your heart (Devarim 11:13)
The Source for the Mitzvah of Tefillah
Anyone who is asked the question, “What is the source for the mitzvah of tefillah in the Torah?” will probably respond by quoting three words from our Parsha (11:13), “וּלְעָבְדוֹ בְּכָל לְבַבְכֶם— and to serve Him with all your heart,” adding the comment of the Sifrei (Devarim, siman 41): “This refers to tefillah.” To support this teaching we would cite the words of the Gemara in Masechet Taanit (2a), “איזו היא עבודה שבלב? זו תפילה — what is ‘avodah of the heart’? This is tefillah.” However, when we consult the words of the Rambam in this matter, we will see that while the abovementioned sources may give us the definition of the mitzvah, they do not constitute a Torah commandment to fulfill the mitzvah.
The Rambam (Hilchot Tefillah 1:1) says:
It is a positive mitzvah from the Torah to pray every day, as it says (Shemot 23:25), “וַעֲבַדְתֶּם אֵת ה’ אֱלֹקֵיכֶם — You shall serve Hashem, your God.” Through tradition we have learned that the “avodah” here refers to tefillah, as it says, “וּלְעָבְדוֹ בְּכָל לְבַבְכֶם,” and the Chachamim explained (Taanit 2a) that this refers to tefillah.
Rav Yosef Karo, in his peirush Kesef Mishneh, asks a question:
Why did the Rambam not write that the source of the mitzvah is from the words “וּלְעָבְדוֹ בְּכָל לְבַבְכֶם,” which explicitly refers to the mitzvah of tefillah?
In other words, the question is, why did the Rambam mention the pasuk of “וַעֲבַדְתֶּם,” which does not refer explicitly to tefillah, and then bring another pasuk that clarifies that the avodah here is in the heart, i.e., tefillah, when he could have simply just brought the pasuk of “וּלְעָבְדוֹ בְּכָל לְבַבְכֶם” itself, which would have told us everything?
The Kesef Mishneh answers:
The reason is because the pasuk of “וּלְעָבְדוֹ” is not a mitzvah — a commandment, but rather sippur devarim — a narration; “וְהָיָה אִם שָׁמֹעַ תִּשְׁמְעוּ … לְאַהֲבָה אֶת ה’ אֱלֹקֵיכֶם וּלְעָבְדו … וְנָתַתִּי מְטַר אַרְצְכֶם … — If you will listen … to love Hashem your God and to serve Him … and I will provide rain for your land … “
The fundamental principle we are being taught here is that a mitzvah of the Torah can only be derived from a pasuk that is phrased as a commandment.
This is something that Rambam has set forth in the eighth of the fourteen shorashim with which he prefaced his Sefer HaMitzvot:
It is not possible to introduce a commandment [that is to say, a positive mitzvah] within a pasuk of narrative … and similarly, a prohibition will not appear within a narrative.
The Sefer HaChinuch
In a similar vein, the Sefer HaChinuch (mitzvah 3) takes great care in explaining to us how to read the pasuk regarding the prohibition of Gid Hanasheh (Bereishit 32:33), “עַל כֵּן לֹא יֹאכְלוּ בְנֵי יִשְׂרָאֵל אֶת גִּיד הַנָּשֶׁה … עַד הַיּוֹם הַזֶּה — Therefore, B’nei Yisrael shall not eat the gid hanasheh … until this day.” These are his words:
Not to eat from the gid hanasheh, as it says “therefore, B’nei Yisrael shall not eat the gid hanasheh.” These words “לֹא יֹאכְלוּ— they shall not eat” were not said as a narrative, as if to say that since this episode happened to the father, the children refrain from eating the gid; rather, they are Hashem’s commandment that it not be eaten.
Faithful to his approach, the Sefer HaChinuch writes regarding the mitzvah of Milah:
Parshat Lech Lecha contains one mitzvah, namely, the mitzvah of milah, as it says (Bereishit 17:10), “זֹאת בְּרִיתִי אֲשֶׁר תִּשְׁמְרוּ בֵּינִי וּבֵינֵיכֶם וּבֵין זַרְעֲךָ אַחֲרֶיךָ הִמּוֹל לָכֶם כָּל זָכָר — this is My covenant that you shall uphold between Me and you and your descendants after you, every male among you shall be circumcised,” and [this mitzvah] was repeated in Parshat Tazria (Vayikra 12:3), “וּבַיּוֹם הַשְּׁמִינִי יִמּוֹל בְּשַׂר עָרְלָתוֹ — and on the eighth day the flesh of his orlah shall be circumcised.” Many mitzvot are repeated in numerous places in the Torah, each time for a purpose, as our Chachamim, z”l, have explained them.
The Chinuch has taken pains to distance us from the misconception that the source for the mitzvah of milah is from Parshat Tazria (“after Matan Torah”), and not from Parshat Lech Lecha (“before Matan Torah”). This is simply not so! Parshat Tazria is not “after Matan Torah,” but rather “after Parshat Yitro.” Similarly, Parshat Lech Lecha is not “before Matan Torah,” it is simply “before Parshat Yitro.” Both of these parshiyot are part of Matan Torah, and both were transmitted, in the words of the Ramban in his introduction to Bereishit, “from Hashem’s ‘Mouth’ to Moshe’s ear.” It is indeed true that the background to Parshat Lech Lecha is historical in nature, and therefore we could not learn the mitzvah of milah from the (narrative) pasuk (Bereishit 17:23), “וַיָּמָל אֶת בְּשַׂר עָרְלָתָם — and he [Avraham] circumcised the flesh of their orlah.” Nevertheless, an expression of Tzivui will obligate, even if the background is one of sippur, in the same way that an expression of sippur within a halachic section of the Torah (for example, “וַיַּעֲלוּ עֹלֹת — and they offered burnt-offerings,” at the end of Parshat Mishpatim, 24:5) does not result in a mitzvah. We should note that there are numerous pesukim in that section of Parshat Lech Lecha that contain commands regarding milah. The Sefer HaChinuch clearly chose pasuk 10 as his source, since it is the first pasuk in that section that contains a commandment.
Building the Beit Hamikdash
Based on this principle, the Kesef Mishneh similarly explains why the Rambam (Hilchot Beit HaBechirah 1:1) derived the mitzvah of building the Beit Hamikdash from the pasuk “וְעָשׂוּ לִי מִקְדָּשׁ — they shall make Me a Mikdash” (Shemot 25:8), which was written within the context of the making the Mishkan in the desert, and not from the pasuk “ וְהָיָה הַמָּקוֹם אֲשֶׁר יִבְחַר ה’ אֱלֹקֵיכֶם בּוֹ לְשַׁכֵּן שְׁמוֹ שָׁם — it shall be the place that Hashem your God shall choose to cause His Name to dwell there” (Devarim 12:11), which refers explicitly to the Beit Hamikdash in Eretz Yisrael. In fact, the Sefer Mitzvot Gadol (mitzvat aseh 163) mentions this second pasuk as the source for this particular mitzvah! However, the Rambam did not quote the pasuk in Devarim, since it is not written in the form of a commandment but rather describes the Beit Hamikdash as the setting for the bringing of korbanot. The Rambam quotes the pasuk in Shemot, which is stated as a commandment.
A similar idea is found in the peirush of the Ritva to Masechet Yoma (24b), explaining how the Gemara states that lighting the Menorah is not considered an Avodah of the Mikdash, and even a non‑Kohen is qualified to light. This seems difficult in light of what is said clearly in the pasuk (Bamidbar 8:2) “דַּבֵּר אֶל אַהֲרֹן וְאָמַרְתָּ אֵלָיו בְּהַעֲלֹתְךָ אֶת הַנֵּרֹת — speak to Aharon, and say to him, ‘when you kindle the lights’”!
To this the Ritva answers:
It is possible to suggest that it is for this reason the Torah did not express this as a commandment, i.e., “Speak to Aharon and he will kindle the lights,” in order to teach us that it is not an Avodah for which a non‑Kohen would incur liability if he performed it.
We find this idea discussed among the Acharonim as well. Thus, for example, Rav Meir Simcha HaKohen of Dvinsk, author of the Meshech Chochmah (Shemot 40:2), writes that the correct source for the halachah that building the Beit Hamikdash must be done by day and not by night (Masechet Shevuot 15b) is the pasuk “בְּיוֹם הַחֹדֶשׁ הָרִאשׁוֹן … תָּקִים אֶת מִשְׁכַּן אֹהֶל מוֹעֵד — on the day of the first month … you shall set up the Mishkan” (Shemot, ibid.) and not the pasuk “וּבְיוֹם הָקִים אֶת הַמִּשְׁכָּן — and on the day the Mishkan was set up” (Bamidbar 9:15), as the first pasuk is written in the form of tzivui, while the second pasuk is written in the form of sippur.
From all these examples we can see clearly that the way the Torah chooses to write something determines whether it obligates on a d’oraita level. Pesukim are deemed to be mitzvot only if they are written as commandments.
 This is as opposed to the opinion of the Ramban, who does not count the mitzvah of tefillah in the list of the Taryag.
 [Reflected in the translation of the words “lo yochlu” as “shall not eat.”]
 [In which case, the words “lo yochlu” would translate as “will not eat.”]
 In our humble opinion, it may still be possible to explain the words “lo yochlu” as a narrative on the level of pshat, while the halachah explains it as a commandment, so that there is not necessarily a contradiction between the two peirushim.
 See, however, Rashi’s comments to that pasuk (s.v. v’hayah); “Build for yourselves a Beit Hamikdash in Yerushalayim.” Nonetheless, it appears that Rashi’s intent is not to emphasize the mitzvah of building, but rather the place where it should be built, i.e., Yerushalayim.