The Tosher Rebbe told how when Rav Bertzi, the father of Rav Mordechai of Nadvorna moved to Nadvorna, he used the mikvah of the Maggid Rav Tzvi Hirsch daily. When the mikvah was not in use the rest of the day and the night, the building was locked and the waters of the mikvah remained covered by a heavy wood board as was customary on those days. One day the shamash came to Rav Bertzi to report a strange and inexplicable phenomenon. Although the door was locked, he kept finding the board moved as if someone had entered during the night and toiveled (immersed) in the mikvah.
“But it’s impossible; how could that be?” asked the shamash.
Rav Bertzi’s reply startled the shamash even more: “The neshamos from the olam ha’elyon (supernal heavens above) must immerse in the fiery river Dinur; some of them came here and immersed instead in the mikvah of the Tzemach Hashem L’Tzvi which is equivalent!”
This phenomenon continued into the days when Rav Mordechai of Nadworna was rebbe. The neshamos continued to immerse in the holy mikvah where the Tzemach Hashem, Rav Tzvi Hirsch; Rav Bertzi; and Rav Mordechai all immersed.
The rebbe, Reb Bertzi, was adamant that no change or innovation ever be made to the maggid’s holy mikvah where neshomos toiveled rather than in the Nahar Dinur. (Avodas Avoda Sichos Kodesh Vol. II Behaaloscha pp. 313-314)
