QUESTION: The Gemara says that although a Halachah l'Moshe mi'Sinai teaches that a Vlad Chatas and a Temuras Chatas must be left to die, Rebbi Yishmael cites a verse which teaches that they must be left to die. Why is both a Halachah l'Moshe mi'Sinai and a verse needed to teach the same Halachah? The Gemara explains that the Halachah l'Moshe mi'Sinai alone would not have taught that if one offers the Vlad Chatas or Temuras Chatas as a Korban he is Chayav. The verse is needed to teach that if one offers it, he transgresses a Mitzvas Aseh.

However, an Aseh is not punishable with Malkus. What, then, does the verse add to the Halachah l'Moshe mi'Sinai? Even without the verse (and the Mitzvas Aseh), it is obvious that offering the Vlad Chatas as a Korban is forbidden because of the Halachah l'Moshe mi'Sinai! (Rebbi Akiva indeed does not derive from a verse that an Isur Aseh is involved. The SHITAH MEKUBETZES explains that Rebbi Akiva maintains that since it is a Halachah l'Moshe mi'Sinai, there is no need for a verse to teach an Isur Aseh.)

(a) RAV MEIR ARIK in TAL TORAH cites the MORDECHAI who writes that most laws taught by a Halachah l'Moshe mi'Sinai are only l'Chatchilah. If one ignores or transgresses the Halachah l'Moshe mi'Sinai, what he does is still acceptable b'Di'eved. Accordingly, the Gemara's answer here is straightforward: If not for the verse, one would have assumed that if he transgresses the Halachah l'Moshe mi'Sinai and offers the Vlad Chatas as a Korban, the offering is valid b'Di'eved. The verse teaches that even b'Di'eved the Vlad Chatas is not acceptable.

(b) The RAMBAM (Hilchos Shechitah 5:2, Perush ha'Mishnayos 6:7) implies that a Halachah l'Moshe mi'Sinai differs from a Halachah written explicitly in the Torah in the case of Safek. Although a Halachah l'Moshe mi'Sinai is a Halachah d'Oraisa, and in a Safek d'Oraisa one must conduct himself stringently (l'Chumra), in the case of a Safek which involves a Halachah l'Moshe mi'Sinai one may conduct himself leniently (l'Kula).

The RAMBAN (Sefer ha'Mitzvos, Shoresh Rishon) challenges the Rambam's explanation. Since a Halachah l'Moshe mi'Sinai is mid'Oraisa, it should be treated like any other Mitzvah explicitly written in the Torah, and a case of Safek must be treated l'Chumra.

The Rambam seems to follow his own reasoning expressed elsewhere. The Rambam (Hilchos Kil'ayim 10:27, Avos ha'Tum'ah 16:1, Bi'os Asuros 18:17) maintains that a Safek d'Oraisa is treated l'Hakel mid'Oraisa, and it is treated l'Hachmir only mid'Rabanan. (That is, the Rabanan decreed that a Safek d'Oraisa should be treated stringently.) The Rabanan, therefore, may be lenient in the case of a Safek of a Halachah l'Moshe mi'Sinai, even though a Halachah l'Moshe mi'Sinai has the same status as a Halachah written in the Torah. (See Insights to Shabbos 55:1:c for another example of a Halachah d'Oraisa which is not written explicitly in the Torah and is treated differently from a Halachah d'Oraisa which is written explicitly in the Torah.)

According to the Rambam, the Gemara here means that if not for the verse, a case of a Safek would have been treated leniently, since that is the Halachah in the case of a Safek of a Halachah l'Moshe mi'Sinai. Once the verse teaches an Aseh as well, a case of a Safek must be treated stringently, like every other Safek d'Oraisa.