כֹּל אֲשֶׁר תֹּאמַר אֵלֶיךָ שָׂרָה שְׁמַע בְּקֹלָהּ
R Schwab was understandably perplexed by the rebbe's response until the gabbi clarified matters for him by pointing out that שָׂרָה is an acronym for Shamshon Raphael Hirsch."
Rav Breuer, His Life and Legacy, Kranzler & Landesman, p. 185, footnote 12.