Someone raised on Avodah the following question (see the posts listed here under two different subject lines, “Kinyan on Shabbos??” and “Kinyan on Shabbos? (Har Sinai)” ). The first Shavuos was on a Shabbos. Didn’t we acquire the Torah — doesn’t this imply a qinyan on Shabbos — which is prohibited? What about our being made avadim, servants, of the Almighty? And the event is compared to a wedding, which we don’t perform on Shabbos.
I answered on-list on a technical level — a qinyan is allowed on Shabbos if it’s for the sake of a mitzvah or according to others for the sake of Shabbos. And what could be more for the sake of Shabbos than giving us the covenant that includes Shabbos? (It was previously commanded at Marah, but it’s the version given at Horeb that is binding today.) The Rama famously performed a wedding that was scheduled for Friday but ran late into Shabbos. (There were extreme circumstances, but still, he permitted it.) Etc…
However, I think there is a meta-issue that is more significant to discuss, and therefore I’m elaborating on the Avodah post where I raised that issue here.
The comparison of matan Torah to a qinyan, a wedding or avdus isn’t necessarily halachic. It is more reasonable to think it’s on an aggadic level, and this whole question doesn’t really begin.
Also, given my attitude toward the historical accuracy of aggadita, I wouldn’t assume that placing Matan Torah on Shabbos is a historical claim. Nor would I assume it isn’t. The point is to provide a, not a study of history. History and legend were blindly mixed because the question is just off topic to talmud Torah.
This is actually easier to support mesoretically than assuming that these narratives were intended as historical assertions (in addition to their metaphor). See R’ Daniel Eidensohn’s “Da’as Torah”. Despite what is presented as the “frum” answer today, this is the position of R’ Saadia Gaon, the Rambam, his son R’ Avraham, the Maharsha, the Maharal, the Vilna Gaon, R’ Hirsch, R’ Yisrael Salanter, etc… Because someone might be surprised that this is the actual normative traditional attitude toward aggadita, I’ll give two sources that I already had on-hand.
The first I posted recently. With respect to aggadic stories, the Rambam (introduction to his commentary to chapter Cheileq in Sanhedrin, a little before his list of the 13 articles of faith, identifies three categories of people, two wrong camps, and one right one. The erroneous approaches are: (1) Those who take all the fantastical claims of the stories as literal, find them absurd, and ridicule the Torah for it; and (2) Those who take them as literal, take them seriously, and therefore believe in an absurd distortion of the Torah. The correct approach is (3) to realize that the Torah convey deeper truths via hint and riddle. (Which he laments is a class of students of the Torah that is small and far between, a class in the sense that “the sun is in the class of all suns.)
And from Rav Yisrael Salanter:
We are living now in the period following the German conquest of several districts of France. The German Kaiser has now become the mighty sovereign of many isolated provinces, which he has united into one mighty state. In order to immortalize its victory, the German government changed the appearance of the eagle in its national emblem, making it two-headed instead of one-headed (as it was until now). Historians, writers and poets praise the conquest with exaggerated descriptions. I myself have read the lines, “The German eagle has spread its wings from Memel to Metz. One of its claws grips Koeln, while the other is in Baden.” Instead of detailed and realistic descriptions of international wars, what they record for posterity are symbols and hints that are only well understood by the generation in which the events occurred.
With the changes of time, memory of the events will fade, and all that will remain will be the terse symbolic account. A long time from now, people will read that in German a two-headed eagle spread its wings for 500 miles. Perhaps they will laugh at this, just as they laugh at [the stories in] the aggada.
The same thing happened to us. Chazal used terse symbolic language to describe the events of and before their time, and they recorded the Torah’s wisdom and mussar in epigrams. These sayings were only understood by the people of their generations, and by mequbalim of later generations.
The notion that the forefathers observed the entire Torah, even Rabbinic rulings, is also an aggadic story, and is no more likely or not to be historical. But it’s not even made about the generation in question.
ALL THAT SAID, it seems to be the rules of aggadic stories, even the ones that aren’t historical, that they do not have any of the “good guys” doing something we wouldn’t. And so we still find commentaries trying to justify things on a halachic basis. This shouldn’t be taken to mean they assumed the events actually occurred!
Which was the thing I was trying to do here. I don’t think there is any reason to believe there actually was a qinyan of any sort done on Shabbos as part of Matan Torah. Still, because Chazal use that metaphoric language, it must be able to work halachically — or else they would have chosen different metaphors.