Don't Smell The Hadas

 The Gemarah Sukkah (9a) says that we learn from the possuk 'חג הסוכות שבעת ימים לה that כשם שחל שם שמים על החגיגה כך חל על הסוכה to tell us one is prohibited to benefit from the sukkah.  Tosfos asks that the Gemarah Betzah (30) indicates that the issur is a rabbinic issur because the sukkah is designated for the mitzvah.  Tosfos explains why we need both sevarat of being an issur Torah learned from the possuk and the rabbinic issur of muktzah.  

The Gemarah (37b) says one is allowed to smell an etrog on sukkot since it is designated for eating but not smell a hadas for that is what it is designated for.  Rashi explains that the issue with smelling the hadas is that we learn from sukkah that there is a prohibition to benefit from something designated for a mitzvah.  We see from the Rashi that the yesod of the issur of שחל שם שמים is the issur of הוקצה למצותו not like Tosfos that learns they are two different dinim.  According to Tosfos the issur of שחל שם שמים is a unique issur of hekdesh on a sukkah, according to Rashi it is an issur of being designated for the mitzvah.  This machlokes and נ"מ are further elaborated on in Moadanay Moshe siman 70. 

There is a third approach to the Gemarah (37b) as well.  The Shach (Yoreh Deah 108:22) cites a Mordechai in Pesachim that says we see from the Gemarah that issuray hanah are only prohibited to smell from if they are generally used for smelling.  The Shach asks what is his proof, the Gemarah is an issur of huktzah limitzvato, that is why it is only muktzah for the normal usage but issuray Hanah are always prohibited?  It must be the Mordechai learned the Gemarah is an issur Torah like Rashi but he held the geder of the issur of שחל שם שמים is not like Rashi, a geder of huktzah limitzato, rather like Tosfos that it is an issur of kedusha and yet the Gemarah says it is only assur if it is the normal usage so we see that prohibited things are only assur to smell if it's the normal usage.  The issue is the Rashba Teshuva 849 suggests like the Mordechai.  However, in Teshuva 189 (cited in Aruch Lenair,) he understands that we do not learn out from sukkah to hadas.  So, how did he entertain bringing a prof to issuray hanah from this Gemarah, וצ"ע.