Powtórzonego Prawa 13:1 Komentarz: Rashi, Chizkuni, Sforno & Siftei Chakhamim

את כל הדבר EVERYTHING [I COMMAND YOU] — light precepts as well as grave ones (Sifrei Devarim 82:1),

לא תוסף עליו, “do not add thereto;” the letter ס here has the vowel tzeyre under it.עליו, additional numbers of sheep, goats of bulls to the offerings. Neither must you add other categories of offerings, such as your sons or daughters.

לא תוסף עליו, for you might add something which is despicable in the eyes of the Lord. If, perchance, you would add new ways of the serving the Lord, you have no assurance that such innovation is acceptable to G’d, for instance the burning of one’s children in G’d’s honour.

תשמרו לעשות OBSERVE TO DO — This statement is intended to attach also a prohibition (לאו) to the positive commands mentioned in this section (Sifrei Devarim 82:2), for wherever השמר is used it is a term that implies a prohibition, but the difference between this and an ordinary prohibition is that flagellation is not inflicted for infringing a prohibition resulting from the use of the term השמר in connection with a positive command.

לא תסף עליו THOU SHALT NOT ADD THERETO — as, for instance, to place five chapters in the Tephillin, to employ five species of fruit and plants in the fulfilment of the command of Lulab, to recite four instead of three blessings in the Benedictions of the priests (Sifrei Devarim 82:4; cf. Rashi on Deuteronomy 4:2).