I have a few questions, all from you section "Insights to the Daf" on daf mem alef umud alef, in the section entitled "A Mitzvah that a woman performs when she gets married."
(a) First, you mention the Peru Urivu mitzvah by a woman. What of the Rash, who clearly holds that there is no mitzvah in the kiddushin, and that all of this is a hechsher mitzvah? He certainly would object to the fact that kiddushin is the miztvah of peru urivu. If nothing else, could it be used to resolve the question asked?
(b) Moving onto a different section, the "Insights of the Daf" Continues to "PERSONAL INVOLVEMENT IN PREPARATIONS FOR SHABBOS".
Here, you mention the opinion of the Rambam that it is indeed a mitzvah to prepare for shabbos (which incidentally resolves any questions on the meforshim who hold that kiddushin is a mitzvah...if you would have asked why the gemara brings proof to its "mitzvah" case with a bunch of hechsher mitzvos.) But again, the opinion of the Rash says that these preparations for shabbos are also hechsher mitzvos (if he doesnt hold that, what does he do with the fact that he holds the gemara is discussing hechsher mitzvos and supports itself otherwise?). If he holds preparations for shabbos are not mitzvos but hechsher mitzvos, how does he justify that we allow talmudei chachamim to degrade themselves by doing work that is not a mitzvah but a hechsher mitzvah? If nothing else, this should call into question the Biur Halacha's pshat.
Thanks!
-Yechiel
Yechiel, Cherry Hill, USA
(a) I'm unclear as to the answer you are suggesting to the question regarding what is the "Mitzvah" aspect of "Mitzva Bo Yoser mi'Bashlucho" for a woman in Kedushin. If you are suggesting that the Rosh might hold the Mitzvah is referring to the Hechsher Mitzvah of Peru u'Rivu, then that could be a good answer to this question. Alternatively, the Rosh could hold of the answer given by the Ran (and quoted in the Insight you are referring to), that for a woman to help her husband perform his Mitzvah is also a Mitzvah ("Mesa'yei'a l'Dvar Mitzva").
However, your pretense that the Rosh holds that Kedushin is merely a Hechsher Mitzvah is not necessarily accurate. If you look in the Hagaos Ashri on the famous Rosh I assume you are referring to (Kesuvos 1:12), the Hagaos Ashri seems to say that the Rosh merely holds that Kedushin is not the Mitzvah of Pru u'Rivu "because doing so is not finishing the Mitzvah." This implies that the Rosh agrees that the Kedushin can be called the beginning of the Mitvzah, despite the fact that he goes on to say that one can technically be Mekayem Pirya v'Rivya without getting married. Accordingly, we could answer that the Rosh holds that the Mitzvah here is indeed the Mitvzah of Pirya v'Rivya.
(b) Your proof that the Rosh must hold that preparing for Shabbos is only a Hechsher Mitzvah based on the fact that otherwise the Gemara is bringing a proof from a real Mitzvah to a Hechsher Mitzvah, can be refuted. According to the note in the Hagaos Ashri mentioned above, it could be that the Rosh holds that there is actually a Haschalas Mitzvah of Pirya v'Rivya in Kedushin, which is why the Gemara compares it to a Mitzvah of preparing for Shabbos.
This would also answer your question on the Biur Halachah, as it would turn out that the Rosh would agree with the Rambam. [The Biur Halachah himself seems to take it for granted that this is a Mitzvah and not a Hechsher Mitvzah, as is apparent from Shar Hatziyon 250:9.]
Kol Tuv,
Yaakov Montrose