The Chossid Who Became the Rebbe Rashab’s “Son-in-Law”

A son of Rebbetzin Menucha Rochel, R. Mordechai Dov Ber Slonim lived in Chevron and resembled his grandfather, the Mitteler Rebbe. After showing up at the Rebbe Maharash’s home at 2 am, he became very close to the young Rebbe Rashab, earning the nickname “son-in-law.”

R. Mordechai Dov Ber Slonim was the son of Rebbetzin Menucha Rochel, the daughter of the Mitteler Rebbe, and R. Yaakov Slonim. Born in 5600, he was a child when his family moved from Lubavitch to Eretz Yisrael.

A resident of Chevron, R. Mordechai Dov Ber served as one of the directors of Colel Chabad and was a leading figure in the local Chabad community. He was said to closely resemble his grandfather, the Mitteler Rebbe, in his physical appearance. He visited Lubavitch multiple times and developed a close relationship with Rebbe Maharash and Rebbe Rashab. R. Mordechai Dov Ber passed away on 5 Teves, 5676.


Having lived for decades in the Holy Land, R. Mordechai Dov Ber decided to make the trip to Lubavitch to visit the Rebbe Maharash for the first time. Though he and the Rebbe Maharash had played together as children, his devoted hiskashrus pushed him to travel to his Rebbe.

The trip had been a sudden decision, and he did not inform the Rebbe Maharash in advance that he would be coming. After a long journey, he arrived in Lubavitch at 2 am. Certain that the Rebbe was awake, he went straight to the Rebbe’s home and knocked on the door. The door opened and there stood the Rebbe who greeted him warmly, “Ah! Shalom aleichem R. Moteh Ber!”

R. Mordechai Dov Ber was understandably shocked that the Rebbe recognized him, having last seen him as a young boy almost forty years ago. The Rebbe addressed his wonderment, “Who else would come and bang on my door at 2 am if not R. Moteh Ber!…”


In correspondence with R. Mordechai Dov Ber, the Rebbe Rashab would refer to him as “my son-in-law,” and to his son, R. Schneur, as “my grandson.” The interesting background to this practice was related by Rebbetzin Shterna Sara to R. Ezriel Zelig Slonim (R. Mordechai Dov Ber’s great nephew):

During R. Mordechai Dov Ber’s stay in Lubavitch, the Rebbe Rashab, then a yungerman, would spend many hours in his company. R. Mordechai Dov Ber would share with him Chassidus teachings and many unknown stories of the Alter Rebbe and Mitteler Rebbe that he had heard from his mother, Rebbetzin Menucha Rochel. Whenever someone was looking for the Rebbe Rashab, they knew they could find him with R. Mordechai Dov Ber.

Once, the Rebbe Maharash was searching for the Rebbe Rashab, and finding him with R. Mordechai Dov Ber, he commented, “Sholom Ber, you took for yourself an ‘eidem oif kest’!” (Lit. “a son-in-law to support,” a Yiddish expression for a close friend that one doesn’t part from.)

So dear to him were his father’s words that he began to refer to R. Mordechai Dov Ber as his “son-in-law” and then to his son as his “grandson.”

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