Sanctify Us – But Not on Rosh Chodesh

Question: Why does our nusach for Shabbos Rosh Chodesh specifically exclude the usual formula "kadesheinu bemitzvosecho …" from Mussaf? The Rinas Yisrael siddur has re-inserted this phrase into the nusach.

Answer:

That is a good question for which I do not have a good answer.

Since the question is so good I will elaborate on it. In Mussaf on Shabbos we say "retzei vimnuchoseinu kadesheinu bemitzvosecho…." We say it even when Shabbos is also Yom Tov or one of the Yomim Noraim (in addition to the normal tefillos of the day). The phrase is not said on a weekday Rosh Chodesh, but why isn’t the Shabbos section added when Rosh Chodesh falls on Shabbos?

I have checked the Rambam's nusach and he does include the phrase.[1] I have also checked the nusach of the Abudraham and he, too, has the Shabbos section.[2] Perhaps there is a difference between the nusach of Ashkenaz and Sefarad regarding this point but other than the printed siddurim available to us, I have not found an early source indicating that this is in fact the nusach of Ashkenaz.[3] A number of errors that have no authentic traditional or halachic basis have crept into many standard editions of the printed siddur. Could this be one of them?

The Aruch Hashulchan raises this possibility and is confounded by the absence of the Shabbos section in the Shabbos Rosh Chodesh nusach. He surmises that it is a printing error, sees no reason why it should not be said, and is surprised that no one noticed this before he did. He declares that he does say the missing section.[4]

Apparently, the editors of Siddur Rinas Yisrael felt the same way and corrected the omission. It may be more accurate to use the Rinas Yisrael siddur on Shabbos Rosh Chodesh. You cannot be saying something wrong, since nusach Sefarad does include this section. At worst you are not following the nusach of Ashkenaz for this tefilla. I do not feel confident recommending that everyone who follows nusach Ashkenaz say this section without further research, since this has been the accepted nusach for generations. The nuschaos should not be tampered with flippantly. In my opinion, proper research by experts in the field and consultation with talmidei chachomim (poskim and gedolei hador) should precede a widespread change to the accepted nusach by all Ashkenazim.

If, in your silent Shemone Esrei, you wish to use the nusach found in Rinas Yisrael and follow the opinion of the Aruch Hashulchan; that is acceptable and perhaps even advisable.

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