פורום אוצר החכמה
על דעות הפוסקים שבועות הגלות
I found a Kuntres there that mentions this on page 8. There is no direct quote. It is all from articles or Kuntreisim in the name of previous Kuntreisim in the name of a certain edition of a Sefer. The original wording is long gone. And I’m assuming it is all based on the Hetter to learn Kabbalah these days, which is what the Bal Hatanya quotes him for.