Mishneh Torah, Negative Mitzvot 123-245

Sugya Map

• Issue: The apparent tension between the Torah's prohibition against adding to its commandments (bal tosif) and the established practice and obligation of observing mitzvot d'Rabbanan (Rabbinic enactments). How do we reconcile the divine mandate for an immutable Torah with the dynamic legislative authority of the Sages?
• Nafka Mina(s):
  • The source and scope of authority for Beit Din (Rabbinic court) to institute takkanot (ordinances) and gezeirot (decrees).
  • The halachic status of mitzvot d'Rabbanan: Are they merely advice, or divinely mandated obligations?
  • The parameters for a prophet to introduce new religious practices.
  • The hermeneutical framework for understanding the Torah's legislative intent.
• Primary Sources:
  • Deuteronomy 13:1 (12:32 in some textual traditions): "כל הדבר אשר אנכי מצוה אתכם אתו תשמרו לעשות לא תוסף עליו ולא תגרע ממנו" (Everything that I command you, you shall be careful to do; you shall not add to it, nor subtract from it).
  • Deuteronomy 17:11: "על פי התורה אשר יורוך ועל המשפט אשר יאמרו לך תעשה לא תסור מן הדבר אשר יגידו לך ימין ושמאל" (According to the law that they will instruct you, and according to the judgment that they will tell you, you shall do; you shall not deviate from the word that they will tell you, right or left).
  • Mishneh Torah, Negative Mitzvot 241-245 (and concluding paragraphs A-E).
  • Mishneh Torah, Hilchot Mamrim 1:1-2.
  • Sifrei Devarim 91 (on D'varim 13:1).
  • Talmud Bavli, Sanhedrin 88b.

Text Snapshot

The Rambam concludes his enumeration of Lo Ta'aseh (negative commandments) with a critical discussion on bal tosif and mitzvot d'Rabbanan:

"Not to add to the mitzvot of the Torah. [This applies] both to the Written Law and to its explanation conveyed by the oral tradition, as [Deuteronomy 13:1] states: 'Carefully observe everything which I command you to do. Do not add to it.' Not to diminish from any of the mitzvot of the Torah, as [Deuteronomy, ibid.] continues: '...and do not diminish from it.'" (Mishneh Torah, Negative Mitzvot 241-242)

He then immediately addresses the potential conflict:

"However, if a court, together with the prophet of that age, adds a commandment as an ordinance, a lesson, or as a decree, this is not considered as an addition. He is not saying that the Holy One, blessed be He, commanded us to make an eruv or read the Megillah at its [appointed] time. Were he to say so, he would be adding to the Torah. Instead, we are saying that the prophets and the courts ordained and commanded that the Megillah be read at its [appointed] time in order to recall the praise of the Holy One, blessed be He, the salvation He wrought for us, and His response to our cries, so that we will bless Him, extol Him, and inform the future generations of the truth of the Torah's promise (Deuteronomy 4:7): 'What nation is so great that it has God [close to it....]'. Similar principles apply with regard to all the other Rabbinic commandments, be they positive commandments or negative commandments." (Mishneh Torah, Negative Mitzvot, concluding paragraphs C-E)

Dikduk/Leshon Nuance: The Rambam's careful phrasing, "לא אמר שהקדוש ברוך הוא ציווה אותנו לעשות עירוב או לקרות המגילה" (He is not saying that the Holy One, blessed be He, commanded us to make an eruv or read the Megillah), is crucial. This highlights the intent behind the enactment. The Beit Din does not claim divine origin for the specific content of the mitzva d'Rabbanan, but rather asserts its own authority to legislate, an authority which itself is divinely ordained via D'varim 17:11. This chiluk (distinction) is the lynchpin of his entire position.

Readings

Rambam (Mishneh Torah, Hilchot Mamrim 1:1-2)

The Rambam's position articulated in the Negative Mitzvot text is fully elaborated in Hilchot Mamrim. He establishes the overarching principle that the Great Sanhedrin (or a subsequent Beit Din possessing similar authority) has the power to enact gezeirot (prohibitions to safeguard Torah laws), takkanot (positive ordinances for the general good), and minhagim (customs). The obligation to obey these Rabbinic decrees is d'Oraita, derived from the mitzvat asseh in D'varim 17:11: "לא תסור מן הדבר אשר יגידו לך ימין ושמאל" (You shall not deviate from the word that they will tell you, right or left).

Chiddush: Rambam's central innovation is his precise distinction between bal tosif and Rabbinic enactments. Bal tosif, he explains, prohibits a prophet or Beit Din from claiming that God Himself commanded a new mitzva (e.g., a "sixth corner" for tzitzit or a "fifth species" for lulav). This would falsely attribute a command to God, thereby "adding" to His Divine will. However, when a Beit Din institutes a takkanah or gezeirah, they are not claiming it is a divine command. Rather, they are exercising their own divinely granted authority (from D'varim 17:11) to legislate for the welfare of the Jewish people and the fence around the Torah. Thus, the takkanah itself is Rabbinic, but the obligation to obey the takkanah is d'Oraita. This elegant solution allows for Halachic dynamism without compromising the immutability of the Torah miSinai.

Ramban (Hassagot al Sefer HaMitzvot, Shoresh Rishon)

The Ramban, in his Hassagot on Rambam's Sefer HaMitzvot, fundamentally challenges this approach to bal tosif. While he agrees that mitzvot d'Rabbanan are binding, he struggles with Rambam's precise definition of bal tosif.

Chiddush: Ramban argues that bal tosif is a broader prohibition, applying to any addition to the Torah's commandments, regardless of whether one claims it to be d'Oraita or d'Rabbanan. He posits that if a Beit Din were to institute a mitzva that appears to be a direct addition to a Torah mitzva (e.g., adding a fifth parsha to tefillin), even if they acknowledge it's Rabbinic, it would still violate bal tosif. How then do mitzvot d'Rabbanan exist? Ramban suggests that they either fall into categories not covered by bal tosif (e.g., monetary regulations, or yom tov sheini in chutz la'aretz which are not chovas gavra in the same way as mitzvot from Devarim 13:1), or they are understood as extensions or safeguards of existing mitzvot, rather than additions. For instance, lighting Chanukah candles isn't adding a new lamed-aleph mitzva to the Torah's 613, but rather a hoda'ah (expression of gratitude) enacted by the Sages, whose observance is mandated by D'varim 17:11. The Ramban emphasizes that the Beit Din's power to legislate is not an unlimited license to "add" mitzvot, but rather to enact gezeirot and takkanot that are distinct in their nature and presentation from the original 613 mitzvot.

Friction

The Strongest Kushya

The most penetrating kushya against the Rambam's chiluk (distinction) is that it appears to render bal tosif almost toothless regarding Rabbinic legislation. If the Beit Din can simply say, "This is our enactment, not God's," and then command its observance by virtue of D'varim 17:11, what practical constraint does bal tosif impose on them? The Torah says, "לא תוסף עליו" – do not add to it. The it (עליו) refers to the entirety of the divine corpus. Whether a new mitzva is presented as directly from God or as a Rabbinic institution derived from a separate divine command to obey Rabbis, it still appears to be an addition to the religious obligations of the Jewish people. For example, if the Torah commands one bracha before bread, and the Rabbis institute two, is that not an "addition" in practice, even if verbally differentiated? The very act of legislating new religious duties, even with an attribution to human authority, seems to expand the "body" of mitzvot, which bal tosif ostensibly forbids. This seems to be the Ramban's underlying concern: the phenomenological reality of a new mitzva being added, irrespective of its stated origin.

The Best Terutz (Rambam's Defense)

Rambam's terutz is robust and relies on a fundamental distinction in metaphysics of command. The prohibition of bal tosif targets the source attribution of a commandment. It forbids fabricating a divine command. When a Beit Din institutes a mitzva d'Rabbanan, they are not claiming that Hashem commanded us to light Chanukah candles. Rather, they are stating that they, the authorized interpreters and guardians of the Torah, have instituted this practice. The obligation to obey this Rabbinic institution, however, stems from a separate, explicit divine command: "לא תסור מן הדבר אשר יגידו לך ימין ושמאל" (Deuteronomy 17:11).

Therefore, there are two distinct layers of command:

1. Direct Divine Commands: The 613 mitzvot of the Torah, which cannot be added to or subtracted from by attributing new commands to God.
2. Divine Command to Obey Sages: The mitzva of shema b'kol chachamim (listening to the voice of the Sages), which empowers the Sages to create new takkanot and gezeirot. When they do so, they are not adding to the content of God's direct commands, but rather defining the application and safeguards for the existing Torah, or commemorating events, under their divinely delegated authority. The mitzva d'Rabbanan is thus not an "addition" to the Torah in the sense forbidden by bal tosif, but an exercise of the Beit Din's inherent authority, itself a mitzva d'Oraita. The eruv or Megillah reading are not presented as "614th mitzvah from Sinai," but as Rabbinic obligations, whose observance is commanded d'Oraita through the lens of D'varim 17:11. This chiluk safeguards the immutability of the Torah's core while allowing for flexible Halachic development.

Intertext

1. Sifrei Devarim 91 (on D'varim 13:1): The Sifrei provides a crucial early source for understanding bal tosif. It states: "לא תוסף עליו ולא תגרע ממנו, מה תלמוד לומר? לא תוסיף על דברי תורה ולא תגרע מהם." (Do not add to it nor subtract from it, why does the verse state this? Do not add to the words of Torah nor subtract from them.) The Sifrei then provides examples that align with Rambam's interpretation, focusing on direct additions to existing Torah mitzvot, such as adding a fifth species to the lulav or a fifth tzitzit string. This suggests that bal tosif is concerned with altering the form or number of mitzvot as given by God, not with the institution of entirely new practices by the Sages under their delegated authority.
2. Talmud Bavli, Sanhedrin 88b: This gemara discusses the authority of the Beit Din and the mitzva of lo tasur (not to deviate from their word). It famously states: "כל דבר שבמנין צריך מנין אחר להתירו" (Anything instituted by a count/majority requires another count/majority to permit it). This maxim underscores the binding nature and legislative permanence of Rabbinic enactments. It demonstrates that once a Beit Din (with the appropriate authority) institutes a takkanah or gezeirah, it becomes a part of the Halachic landscape, not easily dismissed. This reinforces the idea that mitzvot d'Rabbanan are not ephemeral suggestions but rather serious obligations, whose authority is derived from the Torah itself.

Psak/Practice

The Rambam's nuanced approach has become the bedrock of psak regarding the authority of mitzvot d'Rabbanan. His view, that bal tosif prohibits claiming divine origin for new mitzvot, while D'varim 17:11 mandates obedience to Rabbinic enactments, is universally accepted. This allows for the dynamic evolution of Halacha through the ages, enabling Chazal and subsequent Poskim to institute gezeirot (protective decrees), takkanot (positive ordinances), and minhagim (customs) necessary for the spiritual and physical well-being of the Jewish people, without compromising the eternal truth and integrity of the Torah miSinai. Thus, mitzvot d'Rabbanan are considered binding d'Oraita not in their intrinsic content, but in the obligation to adhere to the Sages' words.

Takeaway

The Rambam masterfully navigates the tension between the Torah's immutability (bal tosif) and the need for Halachic development, establishing that Rabbinic legislation derives its binding power from a distinct divine command to obey the Sages, rather than constituting an "addition" to God's direct mitzvot. This brilliant chiluk ensures both continuity and adaptability within the Halachic system.