Halachaהלכה

Bal Tosif and Lo Sasur: Adding and Subtracting from Torah

These twin prohibitions forbid adding new commandments to the Torah or subtracting from existing ones. The sources explore the Biblical foundation of these laws, their application through rabbinic authority, and the crucial distinction between legitimate rabbinic enactments and unauthorized innovations that violate these prohibitions.

לֹא תֹסִפוּ עַל־הַדָּבָר אֲשֶׁר אָנֹכִי מְצַוֶּה אֶתְכֶם

12 sources · verified

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Source 1 · Tanach
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Devarim 13:1

Deuteronomy 13:1

A second iteration of the prohibition: 'Everything I command you, you shall be careful to do; you shall not add to it and you shall not subtract from it' — the Torah's self-sealing quality.

אֵ֣ת כׇּל־הַדָּבָ֗ר אֲשֶׁ֤ר אָנֹכִי֙ מְצַוֶּ֣ה אֶתְכֶ֔ם אֹת֥וֹ תִשְׁמְר֖וּ לַעֲשׂ֑וֹת לֹא־תֹסֵ֣ף עָלָ֔יו וְלֹ֥א תִגְרַ֖ע מִמֶּֽנּוּ׃ {פ}

Be careful to observe only that which I enjoin upon you: neither add to it nor take away from it.

Source 2 · Tanach
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Devarim 4:2

Deuteronomy 4:2

The primary source for bal tosif: 'You shall not add to the word that I command you, nor shall you subtract from it' — the twin prohibitions of adding to and subtracting from the Torah.

לֹ֣א תֹסִ֗פוּ עַל־הַדָּבָר֙ אֲשֶׁ֤ר אָנֹכִי֙ מְצַוֶּ֣ה אֶתְכֶ֔ם וְלֹ֥א תִגְרְע֖וּ מִמֶּ֑נּוּ לִשְׁמֹ֗ר אֶת־מִצְוֺת֙ יְהֹוָ֣ה אֱלֹֽהֵיכֶ֔ם אֲשֶׁ֥ר אָנֹכִ֖י מְצַוֶּ֥ה אֶתְכֶֽם׃

You shall not add anything to what I command you or take anything away from it, but keep the commandments of the ETERNAL your God that I enjoin upon you.

Source 3 · Chazal
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Mishnah Sanhedrin 11:3

Mishnah Sanhedrin 11:3

The Mishnah defines the zaken mamre and his liability — a practical application of lo sasur — specifying that he is culpable only when he instructs others to act against established halachic rulings.

חֹמֶר בְּדִבְרֵי סוֹפְרִים מִבְּדִבְרֵי תוֹרָה, הָאוֹמֵר אֵין תְּפִלִּין, כְּדֵי לַעֲבֹר עַל דִּבְרֵי תוֹרָה, פָּטוּר. חֲמִשָּׁה טוֹטָפוֹת, לְהוֹסִיף עַל דִּבְרֵי סוֹפְרִים, חַיָּב:

If one states: There is no mitzva to don phylacteries, and his intention is in order to have others violate matters of Torah, he is exempt from punishment as a rebellious elder. One who disputes matters written explicitly in the Torah is not considered an elder and a Torah scholar, and therefore does not assume the status of a rebellious elder. If, however, he disputed a matter based on rabbinic tradition, e.g., he stated that there should be five compartments in the phylacteries of the head, in order to add an extra compartment to the four established according to traditional rabbinic interpretations of the Torah, he is liable.

Source 4 · Chazal
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Rosh Hashanah 28b

Rosh Hashanah 28b

Talmudic discussion of whether performing a mitzvah more than required (e.g., sitting in the sukkah on Shemini Atzeret) constitutes bal tosif, introducing the key distinction between adding intent and incidental over-performance.

אֲמַר לֵיהּ אַבָּיֵי: אֶלָּא מֵעַתָּה, הַיָּשֵׁן בַּשְּׁמִינִי בַּסּוּכָּה — יִלְקֶה! אָמַר לוֹ, שֶׁאֲנִי אוֹמֵר: מִצְוֹת אֵינוֹ עוֹבֵר עֲלֵיהֶן אֶלָּא בִּזְמַנָּן.

Abaye said to Rava: However, if that is so, that the fulfillment of a mitzva does not require intent, one who sleeps in a sukka on the Eighth Day of Assembly should receive lashes for violating the prohibition against adding to mitzvot, since he is adding to the mitzva of: “You shall dwell in sukkot for seven days” (Leviticus 23:42). Since, according to Rava, even if one did not intend to observe the mitzva of sukka but slept in the sukka for a different reason, his sleeping in the sukka constitutes the fulfillment of a mitzva to dwell there, then, if one did so at an inappropriate time, he is considered to have transgressed the prohibition against adding to the mitzvot. Yet the Sages instituted that in the Diaspora one must observe Sukkot for eight days. Rava said to him: This is because I say that mitzvot can be transgressed only by adding to them in their prescribed times. But if one adds to a mitzva outside of the period of obligation for the mitzva, there is no violation of the prohibition against adding to mitzvot. On the Eighth Day of Assembly there is no longer a mitzva to sleep in the sukka. Therefore, sleeping in the sukka on that day does not constitute a prohibited act.

Source 5 · Chazal
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Sanhedrin 88b

Sanhedrin 88b

The Talmud discusses the zaken mamre (rebellious elder) who rules against the Great Sanhedrin — a paradigmatic violation related to bal tosif — and how defying established rulings undermines Torah authority.

מַתְנִי׳ חוֹמֶר בְּדִבְרֵי סוֹפְרִים מִבְּדִבְרֵי תוֹרָה. הָאוֹמֵר: ״אֵין תְּפִילִּין״, כְּדֵי לַעֲבוֹר עַל דִּבְרֵי תוֹרָה – פָּטוּר. ״חָמֵשׁ טוֹטָפוֹת״, לְהוֹסִיף עַל דִּבְרֵי סוֹפְרִים – חַיָּיב. גְּמָ׳ אָמַר רַבִּי אֶלְעָזָר אָמַר רַבִּי אוֹשַׁעְיָא: אֵינוֹ חַיָּיב אֶלָּא עַל דָּבָר שֶׁעִיקָּרוֹ מִדִּבְרֵי תוֹרָה וּפֵירוּשׁוֹ מִדִּבְרֵי סוֹפְרִים, וְיֵשׁ בּוֹ לְהוֹסִיף, וְאִם הוֹסִיף גּוֹרֵעַ. וְאֵין לָנוּ אֶלָּא תְּפִילִּין, אַלִּיבָּא דְּרַבִּי יְהוּדָה.

MISHNA: With regard to the rulings of the rebellious elder the mishna states: There is greater stringency with regard to traditional rabbinic interpretations of the Torah than with regard to matters of Torah. If one states: There is no mitzva to don phylacteries, and his intention is in order to have others violate matters of Torah, he is exempt from punishment as a rebellious elder. One who disputes matters written explicitly in the Torah is not considered an elder and a Torah scholar, and therefore does not assume the status of a rebellious elder. If, however, he disputed a matter based on rabbinic tradition, e.g., he stated that there should be five compartments in the phylacteries of the head, in order to add an extra compartment to the four established according to traditional rabbinic interpretations of the Torah, he is liable. GEMARA: Rabbi Elazar says that Rabbi Oshaya says: One is liable only for issuing a ruling with regard to a matter whose essence, whose basic obligation, is from matters of Torah and whose explanation is from traditional rabbinic interpretations of the Torah and which includes the possibility to add to it, and if one added to it, one compromises his fulfillment of the mitzva and does not satisfy his obligation. And we have only the mitzva to don phylacteries that meets those criteria. And Rabbi Oshaya’s statement is in accordance with the opinion of Rabbi Yehuda, who says: A rebellious elder is liable only for a matter whose essence is from matters of Torah and whose explanation is from traditional rabbinic interpretations of the Torah.

Source 6 · Rishonim
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Mishneh Torah, Laws of Rebels 2:1–3

Mishneh Torah, Rebels 2:1-3

Rambam codifies both the positive obligation to follow the Sanhedrin and the prohibitions of bal tosif and lo sasur — distinguishing a rabbinic fence (which is permitted) from adding a new Biblical-level commandment (which violates bal tosif).

בַּמֶּה דְּבָרִים אֲמוּרִים בִּדְבָרִים שֶׁלֹּא אָסְרוּ אוֹתָן כְּדֵי לַעֲשׂוֹת סְיָג לַתּוֹרָה אֶלָּא כִּשְׁאָר דִּינֵי תּוֹרָה. אֲבָל דְּבָרִים שֶׁרָאוּ בֵּית דִּין לִגְזֹר וּלְאָסְרָן לַעֲשׂוֹת סְיָג אִם פָּשַׁט אִסּוּרָן בְּכָל [יִשְׂרָאֵל] אֵין בֵּית דִּין גָּדוֹל אַחֵר יָכוֹל לְעָקְרָן וּלְהַתִּירָן אֲפִלּוּ הָיָה גָּדוֹל מִן הָרִאשׁוֹנִים:

When does the above apply? With regard to matters that were not forbidden to create a safeguard for the words of the Torah, but rather resemble other Torah laws. A different principle applies, by contrast, with regard to matters which the court sought necessary to issue a decree and create a prohibition as a safeguard. If the prohibition spread throughout the Jewish people, another Supreme Sanhedrin does not have the authority to uproot the decree and grant license even if it was of greater stature than the original court.

Source 7 · Rishonim
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Sefer HaMitzvot, Negative Commandments 313–314

Sefer HaMitzvot, Negative Commandments 313-314

Rambam counts both bal tosif and lo sasur as distinct negative commandments, clarifying that bal tosif applies when one adds a new commandment while presenting it as Biblically mandated, not merely when performing an extra act of piety.

הזהירנו מהוסיף בתורה לא בכתוב ולא במקובל, והוא אמרו לא תוסיף עליו, ובבאור אמרו במקומות רבים ועובר משום בל תוסיף, עברת על בל תוסיף. (ראה, הלכות ממרים פ"ב): הזהירנו מגרוע התורה לא מהכתוב ולא מהמקובל. והוא אמרו ולא תגרע ממנו, ובמקומות רבים אמרו עובר משום בל תגרע, עברת על בל תגרע. (ראה, שם):

He prohibited us from adding to the Torah, both to what is written and to what is received. And that is His saying, "do not add to it" (Deuteronomy 13:1). And in the explanation, they said in many places, "and he transgresses on account of, do not add"; "you have transgressed, do not add." (See Parashat Re'eh; Mishneh Torah, Rebels 2.) He prohibited us from subtracting from the Torah, neither from what is written nor from what is received. And that is His saying, "and do not subtract from it" (Deuteronomy 13:1). And in many places, they said, "and he transgresses on account of, do not subtract"; "you have transgressed, do not subtract." (See Parashat Re'eh; Mishneh Torah, Rebels 2.)

Source 8 · Rishonim
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Kuzari 3:41

Kuzari 3:41

The Kuzari defends the Oral Torah's rabbinic enactments as consistent with the spirit of the Written Torah, addressing the apparent tension between rabbinic legislation and the prohibition of bal tosif.

לֹא נֶאֱמַר זֶה אֶלָּא לֶהָמוֹן, כְּדֵי שֶׁלֹּא יְחַדְּשׁוּ מִשִּׂכְלָם וְיִתְחַכְּמוּ מִדַּעְתָּם וְיִקְבְּעוּ לְעַצְמָם תּוֹרוֹת מֵהַקָּשָׁתָם כְּמוֹ שֶׁעוֹשִׂים הַקָּרָאִים, וּמַזְהִיר לִשְׁמֹעַ מִן הַנְּבִיאִים אַחֲרֵי מֹשֶׁה וּמִן הַכֹּהֲנִים וְהַשּׁוֹפְטִים, כְּמוֹ שֶׁאָמַר בַּנָּבִיא: נָבִיא אָקִים לָהֶם מִקֶּרֶב אֲחֵיהֶם כָּמוֹךָ וגו', וְאָמַר בַּכֹּהֲנִים וּבַשּׁוֹפְטִים שֶׁיִּהְיוּ דִּבְרֵיהֶם נִשְׁמָעִים. וְהָיָה מַאֲמָרוֹ: לֹא תוֹסִיפוּ עַל הַדָּבָר אֲשֶׁר אָנֹכִי מְצַוֶּה אֶתְכֶם, עַל מַה שֶּׁצִּוִּיתִי אֶתְכֶם עַל יְדֵי מֹשֶׁה וְעַל יְדֵי נָבִיא מִקִּרְבְּךָ מֵאַחֶיךָ, עַל הַתְּנָאִים הַנִּזְכָּרִים בַּנְּבוּאָה, וּמַה שֶּׁנִּקְבְּצוּ עָלָיו הַכֹּהֲנִים וְהַשּׁוֹפְטִים מִן 'הַמָּקוֹם אֲשֶׁר יִבְחַר ה', מִפְּנֵי שֶׁהֵם נֶעֱזָרִים בַּשְּׁכִינָה

They were recommended to listen to the post-Mosaic prophets, the priests and judges, as it is written: 'I will raise them up a prophet . . . and he shall speak unto them all that I shall command him' (Deuteronomy 18:18). With regard to the priests and judges it is said that their decisions are binding. The words: 'You shall not add,' etc., refer to 'that which I commanded you through Moses' and any 'prophet from among thy brethren' who fulfils the conditions of a prophet. They further refer to regulations laid down in common by priests and judges 'from the place which thy Lord shall choose.' For they have divine assistance, and would never, on account of their large number, concur in anything which contradicts the Law. Much less likelihood was there of erroneous views, because they had inherited vast learning, for the reception of which they were naturally endowed.

Source 9 · Rishonim
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Sefer HaIkkarim III:16

Sefer HaIkkarim, Maamar 1 1:3:16

Albo argues that the immutability of the Torah — expressed through bal tosif and lo sasur — is one of the fundamental principles of the Jewish faith, distinguishing the Mosaic Torah from all other divine communication.

ומה שראוי שנאמר בזה ללמד זכות על חכמי ישראל המדברים בזה וכיוצא בו, הוא כי כל איש ישראל חייב להאמין שכל מה שבא בתורה הוא אמת גמור, ומי שכופר בשום דבר ממה שנמצא בתורה, עם היותו יודע שזהו דעת התורה, נקרא כופר, כמו שאמרו רבותינו ז״ל בפרק חלק, שכל האומר כל התורה כולה מפי הגבורה חוץ מפסוק אחד שאמרו משה מעצמו, עליו נאמר כי דבר ה׳ בזה, והוא בכלל האומר אין תורה מן השמים.

Accordingly it might be said that Rabbi Hillel’s opinion was that the texts of Isaiah and the other prophets can not be cited to prove the coming of the Messiah, but that he believed in the coming of the redeemer on the basis of tradition and hence was not excluded from the community of Israel and not classed as a sinner.

Source 10 · Hasidic
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Noam Elimelech, Noach

Noam Elimelekh, Sefer Bereshit, Noach

The Noam Elimelech uses the concept of not adding or subtracting to explore the tzaddik's role as a faithful transmitter of Torah — the rebbe must convey divine teaching without personal embellishment, neither adding nor diminishing.

דהיינו שצריך להרגיז היצ"ט על היצה"ר לשבר כח הפניות עד שיזכה שיהיה אהבתו שלימה, ועל ידי זה הוא מעלה גם את האהבות החיצונות שהיו בו מתחילה, מעלה אותם ג"כ אל הקדושה, כמ"ש חז"ל 'הזדונות נעשים כזכיות'. וזהו שאנו אומרים "אהבת עולם אהבתנו", פירוש גם אהבת עוה"ז שהיתה לנו מתחילה, "אהבתנו", כלומר גם הם אהובים לפניך כשאנו מעלים אותם אל הקדושה, "חמלה גדולה

as above. "And he waited more etc and she did not come back etc" (Gen. 8:12) the explanation comes from the verse "a great voice that did not add" (Deut. 5:19) and the explanation of Rashi: 'did not interrupt', meaning, that there are other levels in human beings in which one does not stop thinking ever, seeing that one's deeds are never good enough to their own eyes and one is always seeing defects on them, and is always trying to go back and do teshuvah, and this is "she returned to him again" - a person should always be a ba'al teshuvah.

Source 11 · Hasidic
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Toldot Yaakov Yosef, Va'etchanan

Toldot Yaakov Yosef, Vaetchanan

The Toldot Yaakov Yosef offers a Chassidic reading of bal tosif, suggesting that the prohibition against addition points to the need for total self-nullification before the Torah — human additions reflect ego and the desire to impose one's own understanding.

ויאמר ה' אלי (עוד) אל תוסף דבר אלי עוד בדבר הזה. הכוונה, גם אם ירצה לדבר ענין תפלה זאת שיזכה לדבק למעלה, ובזה לא יוכל להתחבר עמהן, כמו שכתבתי ענין זה במ"א, ולכך לא תוסף דבר אלי בדבר הזה, אפילו על ידי דבור, והבן.

Source 12 · Hasidic
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Kedushat Levi, Va'etchanan

Kedushat Levi, Deuteronomy, Vaetchanan

Reb Levi Yitzchak of Berditchev connects the prohibition of bal tosif to the theme of divine unity — adding to the Torah introduces multiplicity into what is essentially one, indivisible divine wisdom.

או יבואר, שמע ישראל ה' אלהינו. הכלל, השם יתברך הוא אחדות הפשוט אבל באמת הבחינה לעבוד אותו יתברך יש חילוק יש שעובד אותו במדת אהבה ואחד עובד אותו במדת יראה ואחד בבחינות התפארת וכן בשאר המדות אשר אינם שוים. וזהו הרמז כי שם הוי"ה ברוך הוא הוא שם עצמותו ושם אלהים רומז על בחינות עבודתו יתברך. וזהו שפירש רש"י ז''ל בכמה מקומות שם אלהים מורה לשון רבים, כי באמת בעבודתו יש בחינות הרבה כנ''ל. ובאמת האדם כל מדה ומדה שעובד בה את הבורא ברוך הוא צריך לדבק בשם הוי"ה ברוך הוא שהוא מורה על מדת אחדות הפשוט. וזהו הרמז בפסוק ואתם הדבקים בה' אלהיכם, כלומר שאתם צריכים לדבק בה' אלהיכם, היינו כל אחד ואחד כפי עבודתו צריך לדבק הכל בה' שהוא אחדות הפשוט אף על פי שהעבודות המה מחולקים צריך לדבק הכל בה' כנ"ל. וזהו הרמז ה' אלהינו. ה', הוא המורה על עצמותו יתברך שהוא אחדות הפשוט. אלהינו, זה שאנו עובדים אותו יתברך. ובאמת יש בה בחינות רבות אבל אנחנו צריכין לדבק כל עבודתינו בו יתברך וזהו ה' אחד, צריך לדבק בה' שהוא מורה על אחדותו יתברך שמו:

A somewhat different approach to the verse ‎שמע ישראל ה' ‏אלוקינו ה' אחד‎, “Listen O Israel the Lord our G’d, the Lord is ‎One,” concentrates on the differences in meaning between the ‎different names of G’d used by Moses in a single verse. We know ‎that the tetragram, i.e. the four-lettered name of G’d spelled ‎י-ה-ו-‏ה‎, describes the Essence of G’d, “unity” in its simplest most ‎uncomplicated form. While this is most certainly true, people ‎who worship G’d do so on different levels, motivated by different ‎considerations so that by implication even while worshipping the ‎one and only Creator, they somehow “undermine” this concept of ‎G’d’s Unity by the multifaceted approach to Hashem. Moses ‎is aware of this, and he takes due note of this by first speaking of ‎G’d as the tetragram, i.e. Hashem, while immediately almost ‎‎“correcting”: himself by switching to the name ‎אלוקים‎, i.e. ‎אלוקינו‎, a specific attribute of G’d, one that alludes to the many ‎facets of G’d in the eyes of His worshippers. Moses describes Him ‎at this stage as “our G’d,” instead of as a universal G’d. This idea is ‎also reflected in Rashi’s commentary, who states on several ‎occasions that the reason that the very name ‎אלוקים‎ is always in ‎the plural mode, reflects the fact that even people worshipping ‎Him, exclusively, do not relate to Him from identical ‎perspectives, thus creating the impression that He is not an ‎absolute Unity. Moses therefore is at pains to teach us that we ‎must not allow such considerations to undermine our perception ‎of Him as total Unity, hence he concludes with the words ‎ה' אחד‎, ‎‎“Hashem is absolute Unity,” once more. Each one of us, ‎regardless of whether we worship G’d out of fear of punishment, ‎because we have learned to love Him, because we wish to establish ‎a relationship known as ‎דבקות‎, “cleaving to Him,” must never lose ‎sight of the fact that He is the only true Unity that exists, and ‎that anything less than this Unity, is somewhat removed from ‎the Essence of the Creator Whom we worship as such.‎