We were previously taught in the Mishna (Yevamot 4:13, 49a) that ‘if a man’s wife died, he is permitted to marry her sister’, and similarly, ‘if his yevama died, he is permitted to marry her sister’.
Interestingly, Rav Yosef points out in today’s daf (Yevamot 50a) that this teaching appears to be little more than a reworking of an explicit verse (Vayikra 18:18) where we are taught: וְאִשָּׁה אֶל אֲחֹתָהּ לֹא תִקָּח לִצְרֹר לְגַלּוֹת עֶרְוָתָהּ עָלֶיהָ בְּחַיֶּיהָ – ‘do not marry a woman to be a rival to her sister exposing her nakedness while her sister is alive’. As such, he states כאן שנה רבי משנה שאינה צריכה – ‘Rebbi has taught here a Mishna that is unnecessary’.
Challenging this assertion, Tosfot notes that there are – in fact – a number of instances in the Mishna where a Tanna teaches something that is explicit in a verse – which tells us is that part and parcel of Torah teaching is to teach ideas that are already known alongside those that may not be well known.
Reflecting on this, I am reminded of the opening words of the ‘Mesillat Yesharim’ where Rabbi Moshe Chaim Luzzatto (Ramchal) states how, ‘this book was not written to teach people that which they do not know. Instead, it was written to remind them of that which is already known and is already familiar to them.. but even though these ideas are already well known… so too, we often overlook and forget these ideas’ – and as it happens, I quoted these words just a few weeks ago.
During a conversation with an up-and-coming Torah teacher I suggested that she should start thinking about writing a book. She responded by saying that she’d considered doing so, but then added that since most of the ideas that she shares are drawn from the scholarship of others, she was unsure whether is it really appropriate for her to write a book?
In my response I mentioned a number of other great Torah teachers who, though perhaps not renowned for their own original insights, are truly brilliant at framing and explaining ideas and how grateful I am for the books they have written. I then told her that great ideas need to be effectively framed and explained and that she was gifted in doing so. And I then referenced the above-mentioned words of the Ramchal to emphasise how sometimes the greatest of books are there to remind us of ideas that – though known – have unfortunately been overlooked or forgotten.
Yes, there will be those like Rav Yosef who say – like he did about the above-mentioned Mishna, that it is ‘unnecessary’. But as Tosfot comes to teach us, part of the transmission of the Torah is to teach ideas that are already known alongside those that may not be well known.