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The Prohibition to Add or Detract Mitzvos


Adding or detracting mitzvos from the Torah has been a historic point of contention between Torah Judaism and movements that tried to modify it. What is included in this issur? After fulfilling the requirement of a mitzva, can one add more at will? Can one just carry around, for example, his esrog, for an additional mitzva? Does one who lays Rabbenu Tam tefillin transgress the aveira of bal tosif according to Rashi? What can one do if he wants to fulfill a mitzva in a way that satisfies all the different opinions? And the opposite – can one decide what bedieved is good enough for him? Of this, and more, in the following article.

Adding and Subtracting

This week’s parashah records Moshe’s admonishment: “Everything I command you you shall be careful to do it. You shall neither add to it, nor subtract from it.” (Devarim 13:1). Adding and subtracting mitzvos are counted as two separate mitzvos by most of the Rishonim who recorded the 613 mitzvos (Halachos Gedolos mitzva 187-188; Rambam Sefer Hamitzvos, negative mitzvos 313-314; Yereim 381-382; Smag negative mitzvos 364-365 and others). One is forbidden to add or subtract from the mitzvos of the Torah. This week’s article will detail what is included in this issur.

The Torah is Complete

Sefer Hachinuch (mitzva 454) explains the reason for this mitzvah: the Torah is a complete, whole entity and does not require additions, amendments or alterations. Rabbenu Bachye writes (Bereshis 17:1; Shemos 25:38) that the passuk in Tehilim (19:8) “Toras Hashem temima – Hashem’s Torah is complete” teaches that one may not add or subtract from the Torah. He learns this from the syntactic similarity of the word temima. After having performed the circumcision, Hashem told Avraham Avinu he would be tamim – whole, complete. He would be perfect and need no further perfection. The Menorah, the vessel in the Mikdash that represented the Torah’s wisdom, must be made exactly from one kikar of gold, not more, nor less. This is to illustrate the wholeness and utter perfection of the Torah – it needs not one added letter, nor one letter less.

One of the 13 Principals

The Rambam in his preface to the Mishna, records this mitzva as the ninth of the 13 ikarei emuna, the Thirteen Principals of Faith. In his More Nevuchim he explains this concept: Judaism is based on the fact that the Torah’s rules — the mitzvos — are not a dynamic, evolving entity. The Torah is perfect and unchanging. There is no way nor is there a need to make amendments and alterations to meet the needs of the changing times. If it would depend upon the scholars of every generation, the basic laws of Judaism would be, by now, very different from the G-d given gift of Torah.

The Torah’s laws are carved in stone, but their practical application vary from one generation to the next, according to he needs and times.

Chachomim have limited abilities to institute changes. The changes may be for one of the following reasons:

1) For the purpose of creating additional boundaries, to be used as a mechanism to ensure the actual laws of the Torah are preserved.

2) A hora’as shoa, A temporary change. Even when this is the case, chachomim are responsible to make known that this is not the regular practice, nor is it a change in the Torah itself, but a hora’as shoa-a temporary ruling. This way the Torah will remain forever in perfection, as it was given to us at Sinai.


Among the Rishonim we find differences in opinion how to define this mitzva and what is included in it.

Sifri – Expression of a Difference

According to the Sifri (psikta 82) there is a prohibition against changing the details of a mitzva such as the number of tzitzis in a garment, or to take two, or four species along with the lulav on Succos. Placing five, or three scrolls of parchment inside the tefillin; reciting five – or three brachos in Birkas Kohanim also fall in with this explanation. This coincides with the Mishna (Zevachim 80a) that warns against adding matanos of blood on the Mizbayach over those required for each specific korban – a korban that requires one gift, just that must be offered, and adding more violates the issur of bal tosif. And the opposite, too, is true – for a korban that requires four matanos — no less may be offered. This is also Rashi’s opinion (Devarim 4:2; 13:1), the Yereim (371:372), the Smag (negative mitzva 365) and the Smak (188). This is also the understanding of the words of the Ra’avad (Mamrim chapter 2:9) and the Chinuch (454-455).

The Rambam

The Rambam (Mamrim, chapter 2:9) understands that the prohibition is to explain the mitzvos differently from their original form — making changes in the mitzvos, from either the written or oral Torah.


The Torah states in Shemos 23:19: “Do not cook a kid in its mother’s milk.” From the Oral Tradition, we learn that the Torah forbade both the cooking and eating of milk and meat, whether the meat of a domesticated animal or the meat of a wild beast. The meat of fowl, by contrast, is permitted to be cooked in milk according to Scriptural Law. Now if a court will come and permit partaking of the meat of a wild animal cooked in milk, it is detracting from the Torah. And if it forbids the meat of fowl cooked in milk saying that this is included in “the kid” forbidden by the Scriptural Law, it is adding to the Torah.

However, the court may say: “The meat of fowl cooked in milk is permitted according to Scriptural Law. We, however, are prohibiting it and publicizing the prohibition as a decree”. Such an approach is not adding to the Torah. Instead, it is creating safeguards for the Torah.

The Lechem Mishne adds that saying for example, that eating meat of a wild beast cooked in milk is an issur d’rabonon rather than a d’oraysa which it truly is violates the issur of bal tigra.

There is a machlokes in the way to explain the Rambam’s shita here. Rabbi Yerucham Fischel Perla in his Biur on Sefer Hamitzvos (aseh 5) writes that this issur also includes one who invents an additional mitzva, or says that a mitzva from the Torah is not true or is limited in time. But the Iggros Moshe (Orech Chayim part 1, chapter 14) understands here that only changing details of a mitzva is included in this issur. Inventing a new mitzva or denying the existence of a mitzva from the Torah is not included in the issur.

The Zohar (Mishpatim 124) adds a deeper understanding of this mitzva. The Zohar explain that the entire Torah is all Hashem’s Holy Name. One who adds even one letter, or subtracts from it is sabotaging Hashem’s Name.

The Ramban

The Psikta Zutra (Devarim 4:2), Ramban (ibid) and Ritva (Makkos 23b) agree that this issur includes only making up a new mitzva, one such as the holiday Yerovam ben Nevat invented – a holiday in Cheshvan (Meachim I 12:33). Mordechai and Esther did not institute the holiday of Purim until they found a source for it in the Torah, as described in the Gemara (Megila 14a). The Rambam also explains the issur of lo sigrau as not canceling a mitzva that is written in the Torah.

Interestingly, the Ramban in this week’s parashah explains the mitzva differently. He explains that the mitzva here must be seen in context of the previous psukim, those that speak of idol worship. According to the Ramban, we are warned here not to serve Hashem in a way that differs from what is described in the Torah, making sure not to learn from the other nations how to serve their idols. The Chizkuni, Abarbanel and Or Hachayim all see this mitzva as pertaining to service of G-d – there is a specific mitzva to refrain from mimicking the manners of in which idolaters serve their gods when serving Hashem in the Beis Hamikdash.

Sefer Haikarim sees this mitzva in this context too, but with wider ramifications. He explains (Ma’amar 3, chapter 14) that the Torah here warns not to change the details of any existing mitzva as idol worshipers are accustomed to doing – every worshiper adds or subtracts from his idol’s worship upon whim. Therefore, this warning is written in the context of the admonishment not to learn Avoda Zara from the nations of Canaan.

And indeed, the Gra (Aderet Eliyahu, Devarim 13:1) and Rabbi Yerucham Perla both understand that there are two issurim involved in changing the Torah: one – not to invent a new mitzva (in accordance with the Ramban’s shita) and the other – not to change an existing mitzva (following the Sifri). The Gra learns the two mitzvos from different psukim. The issur of inventing a new mitzva or cancelling an existing mitzva is found in Parashas Va’eschanon, while the issur of changing the mitzvos has its source in this week’s parashah.

Failed Performance – Lo Sigrau?

The Rashba asks (Rosh Hashana 16a) how Chazal could have forbidden sounding the shofar on Rosh Hashana when it falls on Shabbos since such an institution consists of the issur of lo sigrau – not to subtract from the mitzvos. He answers that this takana was instituted in order to prevent the issur of carrying the shofar in reshus harabim. In this case there is no issur of lo sigrau, since the Torah demands a person to follow the institutes of the Rabbonim: “…You shall not divert from the word they tell you, either right or left” (Devarim 17:11).

The Turei Even (Rosh Hashana 16a), deduces from this that if a  person refrains from performing a positive mitzva, for an unjustified reason, in addition to failing to perform the mitzva, transgresses a negative mitzvah-bal tigra. According to Rav Yehuda’s opinion (Maseches Temura 3a) that transgressing a negative mitzva is punished with lashings, this does not add up – it is unheard of that one who refrained from a positive mitzva is deserving of lashings. The Imrei Bina answers that when there is a negative mitzva whose only purpose is to preserve the positive mitzva, the punishment for it cannot be more severe than the punishment for the positive mitzva. Therefore, lashing is not meted out for bal tigra in this situation.

Ba’al Ha’akeida expresses an opinion similar to this Rashba. This can be understood from his comment on the Mishna (Zevachim 80a): if the blood of two korbanos got mixed — one Tano necessitates offering of two matanos, while the other Tano requires four. The question here is what to do – give four gifts and the blood from the first korban will constitute an aveira of bal tosif, or give one and then the aveira will be lo sigrau? Which issur should be avoided more? Rabbi Eliezer rules to give four so as not to sin with lo sigrau while Rabbi Yehoshua says that giving one matana is preferable so as not to sin with bal tosif. Halacha follows the opinion of Rabbi Yehoshua. Ba’al Ha’akeda here explains that it is better to refrain from performing a positive mitzva and not to actively perform a sin of bal tosif.  Therefore, we see here that the kapara of one who did not perform a positive mitzva is lesser than one who actively performed a sin. From this we can deduce that refraining from a positive commandment also includes a negative commandment, just that a passive aveira is of lesser gravity than an active one.

The Punishment

What is the punishment for the sin of subtracting from the Torah? Is it a punishable aveira? The Ramban (Shemos 23:13) is of the opinion that every general negative commandment is not punishable by lashings. Similar to this is the general warning to fulfill all the mitzvos of the Torah, of which all commentators agree that one is not flogged for. According to the Sfas Emes (Rosh Hashana 28b) even if the Rashba is understood along with the Turei Even’s line of reasoning, since lo sigrau is a general warning to perform all the mitzvos of the Torah, one is not flogged for transgressing it. It is important to note here that the Sefer Hachinuch is of the opinion that one is flogged for the sin of lo sigrau.

Other Explanations of the Rashaba

Some Achronim (Baruch Ta’am, Sfas Emes, Avnei Nezer) argue with the Turei Even’s approach and are of the opinion that even the Rashba does not mean that every person who refrains from performing a positive mitzva is actually sinning and performing a negative mitzva. This aveira of bal tigra only pertains to a beis din that revokes a mitzva and, for example, announces that the shofar is not to be sounded.

Rabbi Yerucham Perla explains that the Rashba means that only one who changes the definition of the mitzva on a regular basis, such as the institution of refraining from sounding the Shofar when Rosh Hashana falls on Shabbos, or sitting in the Succa only for six days. But a person who refrained from performing a positive mitzva one time does not transgress this negative mitzva.

Rabbenu Se’adya Ga’on

According to Rav Sa’adya Gaon, the mitzva not to change or subtract from the mitzvos is not a mitzva on its own but a general instruction, one of the rules of the Torah, not one of the 613 mitzvos.

Practical Addition or Subtraction

The Turei Even (Rosh Hashana 25) and Mishna Brura (chapter 34:2) both note that one who is too lazy to perform a mitzva properly, relying on bedieved for his mitzva, even if performing the mitzva, transgresses the issur of lo sigrau. He proves this from the Mishna in Zevachim mentioned above – when one is obligated to do more, if he does less, although he did perform the mitzva, he nevertheless transgressed the issur of lo sigrau.

Another ramification is the mitzva of tefillin, for those who lay Rabbenu Tam tefillin. The Mishna Brura writes that one who lays a second pair of tefillin should lay them with the stipulation that if the halacha is as his tefillin are made – they should be for the mitzva and if it follows Rashi’s opinion – this laying should not be a mitzva, so as not to transgress the issur of lo sigrau.

In addition, the Taz is of the opinion that after shaking the Four Species on Succos, one is not permitted to shake less than all four just for chibuv mitzva. Nevertheless, the Elya Rabba does not agree with this approach and writes that if someone does this after having performed the mitzva correctly, it does not constitute the issur of lo sigrau.

Stay Well

The Rashba (New Responsa, chapter 366) explains the Gemara in Maseches Succa: (28a):

It is said of Rabbi Yochanan ben Zakkai that he was not ignorant of anything: Scripture, Mishna, Talmud, Halacha, Aggadah, Biblical grammar, scribal traditions, deductive logic, linguistic connections, astronomical calculations, gematriot, incantations for angels, incantations for demons, incantations to palm trees, proverbs of washwomen, proverbs of foxes, a “Great thing,” and a “Small thing.” A “Great Thing,” is the workings of the Chariot. A “Small thing,” is the legal discourses of Abaye and Rava.

The Rashba explains that the “small things” that Rabbi Yochanan ben Zakkai knew included our Gemara — the “how” of the Torah, the practical ways to perform the mitzvos. But the “great things” are the “whys” of the world, the inner understanding of why things work as they do. The Rashba compares it to a doctor who gives his patient potions to heal him. The Talmud does not explain why those potions – the mitzvos – work in maintaining our optimal health. But in performing those details fully, we ensure our spiritual and physical health – joy and fulfillment in This World and the Next.


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