About this verse, the Torah Temimah cites Arachin (Erchin) 11a: "Where do we derive the requirement of the song (shira) of the Levites from the Torah?... Rav Matna said: From here - 'Because you did not serve Hashem your God with joy and with gladness of heart.' What service is done with joy and gladness of heart? You must say it is song."
Now, there's nothing whatsoever about Devarim 28:47 which by any stretch of meaning would point to the Levi'im or their song. It's obvious that Chazal had in mind the joy and significance of the shira (singing), and one of the sages looked at this pasuk, made a mental association to the Levi'im, and eventually it made its way into the pages of the Talmud. In other words, there IS NO reference to the Levi'im singing in the Torah. But there IS a tradition about the singing, and for whatever reason (actually we'll see the Torah Temimah's reason below) Chazal felt it was important to hang that tradition on a pasuk in the Torah.
And there's nothing wrong or disingenuous about this - so long as one is honest about it and acknowledges that it's merely a pedagogical tool. I say "merely" but I don't mean to diminish its importance. It's a fantastic teaching tool! The problem is when "frumkyte" starts to demand that we all believe that the Torah itself is telling us about shira, when clearly it's not, or that this drash is "built into" the Torah, that Rav Matna received this tradition from Sinai, when clearly many/most/all of these drashot were developed by Chazal as memory tools. Why is it such a big problem to hold this erroneous belief?
- Because it ups the ante on what one is required to believe in order to be considered "frum", incorrectly identifying people who don't believe it as "heretics".
- Because it's not true even from a traditional Torah standpoint, and why should we encourage a misconception of Torah?
- Because when you feed people notions that are untenable, the mind starts to regurgitate, and it's things like this which make people roll their eyes at the Torah tradition and make them want to distance themselves from it.
"We have already written a number of times in our treatise about the question of Aggadic drashot (interpretations) like these, where the intent of Chazal is not to explain the plain meaning of the text [and] to instruct regarding this interpretation literally. Because the truth is that no Scripture ever goes out of its plain meaning. Rather it is that the method of Chazal in holy [writings] is to juxtapose (l'hasmich) every matter that is received [in the tradition] and pass it down from generation to generation using some word(s) in the text of the Torah, so that this matter will have a hint or sign [in the text]. Because according to the law it is forbidden to write down matters within the Oral Torah, and therefore it is good and proper to give each matter that is taught in the Oral Torah a hint and an associated-text (asmachta) in order to remember the matter, since this is the nature of memory, where if there is something with which to associate a matter, it will remain in one's memory..."That's the Torah Temimah's comment on the Gemara in Erchin. Chazal didn't want to write down oral traditions like the shira of the Levi'im, so they attached such traditions to the Torah text. The system of drashot was a fantastic creative project of associative thinking and memorization techniques. Thank you Chazal for creating it, and thank you Torah Temimah for saying it straight!