Among the many Mitzvot discussed in Parashat Re’eih is the Mitzvah of Baal Tosif, not adding to Mitzvot. The Pasuk says, “Eit Kol HaDavar Asher Anochi Metzaveh Etchem Oto Tishmeru LaAsot Lo Toseif Alav VeLo Tigera MiMenu,” “The entire matter that I command you, you shall guard it to do; you shall not add to it and you shall not subtract from it” (Devarim 13:1). Commentators struggle with the fact that this Pasuk seems like a repetition of the Pasuk in Parashat VaEtchanan, “Lo Tosifu Al HaDavar Asher Anochi Metzaveh Etchem VeLo Tigreu MiMenu,” “You shall not add to the word that I command you, nor shall you subtract from it” (Devarim 4:2). The Vilna Gaon answers that the prohibition discussed in VaEtchanan is to add a Mitzvah or subtract a Mitzvah, while the prohibition discussed in Re’eih is to actually perform Mitzvot with an added or subtracted element, such as such as wearing two pairs of Tefillin or wearing Tzitzit on only three corners.
In his Sefer Torah LaDaat, Rav Matis Blum comments that the Pasuk in Re’eih uses the word “Tishmeru,” “you shall guard.” The word “guard” in the Torah refers to a negative commandment, a Lo Taaseh. Therefore, it seems that the Pasuk in Re’eih prohibits adding and subtracting to negative commandments.
Rav Blum continues to explain how one is able to add or subtract to negative commandments. Subtraction is applicable in the case of many prohibitions of eating, where we have a minimum amount which is prohibited. One may think to subtract and claim that because he is eating less than the minimum, his action is permitted. To counter this, the Torah writes not to subtract from Mitzvot Lo Taaseh. Indeed, we have a rule that Chatzi Shiur Assur Min HaTorah, eating half the minimum amount is prohibited from the Torah.
To understand how to add to a Mitzvat Lo Taaseh, we must look at the previous Pasuk in Re’eih, which states, “Ki Gam Et Beneihem VeEt Benoteihem Yisrefu VaEish Leiloheihem,” “For even their sons and their daughters have they burned in the fire for their gods” (12:31). This refers to the service of the deity Molech, which included burning one’s children. We learn that this is prohibited from the Pasuk, “UMiZaracha Lo Titein LeHaavir LaMolech,” “And you shall not give from your children to pass through the fire for Molech” (VaYikra 18:21). Because this Pasuk uses the word “MiZaracha,” “from your children,” and not the word “Zaracha,” “your children,” we learn that the prohibition mainly applies only to giving some but not all of one’s children. One may think that adding to the prohibition and giving all of one’s children to Molech is permitted. However, this is prohibited as it is adding to a Lo Taaseh.
The lesson we learn from Baal Tosif is now clear. If one adheres strictly to the letter of law, he has perhaps not accomplished what the Torah wished him to. Instead, one must remember that adding to and subtracting from a prohibition is still prohibited. It is necessary to go Lifnim MiShurat HaDin, beyond the letter of the law, to fulfill the entire Torah.