As the son-in-law of the Rebbe, even Rabbi Menachem Mendel’s most personal commitments could not be entirely separated from the public sphere. He later commented that on the day of his marriage to Chaya Mushka he had also become bound to the community of chassidim.1

After their wedding the couple moved to Berlin, where both pursued university studies. Extant correspondence and the testimony of people who knew him at the time, including Rabbi Joseph B. Soloveitchik, indicates that these subjects were not R. Menachem Mendel’s primary preoccupation. In Berlin he led a life of intense piety; he fasted, immersed daily in a mikvah, and spent long hours studying Talmud, Kabbalah, Halacha and Chassidism.2 A local Berlin Jew once delivered a letter to R. Menachem Mendel in the middle of the day, and was astounded to find him studying the Jerusalem Talmud while wrapped in tallit and tefillin.3

Away from the chassidic center in Riga, R. Menachem Mendel was free to turn inwards, following his own intellectual interests, “There are people for whom the center and emphasise of their lives is found in the realm of introspection..."and focusing on a personal path of spiritual service. In a letter penned to his father-in-law, Rabbi Yosef Yitzchak, he explicated his introverted orientation: “There are people for whom the center and emphasise of their lives is found in the realm of introspection, in the realm of thought; their main movement - and every living thing moves - is directed inward, to the world that is in their heart, rather than to the world that surrounds them and is outside of them… Whether due to the characteristics of my soul, or to extraneous conditions, it seems that I too am among them.”4

The relative isolation of the young couple was punctuated by long trips to Riga to celebrate the Jewish festivals with Chaya Mushka’s parents. Although R. Yosef Yitzchak spent the High Holiday period of 1929 in the United States, his wife, Rebbetzin Nechamah Dinah, remained in Riga, and a large contingent of chassidim prayed in his synagogue as usual. In letters written at the time in Riga to R. Yosef Yitzchak, R. Eliyahu Chaim Althoiz expressed deep sorrow for the Rebbe's absence, and deep appreciation for R. Menachem Mendel’s presence.5

Chabad chassidim have always striven to spend the High Holiday season - beginning with the days of awe and atonement, Rosh Hashanah and Yom Kippur, and concluding with the joyous celebration of Sukkot and Simchat Torah - with the Rebbe.6 On the morning before Rosh Hashanah the congregation in Riga gathered to recite selichot, but R. Yosef Yitzchak’s absence was so tangible that all stood silent, looking with tear filled eyes to his empty place and unwilling to begin. “The first,” wrote Althoiz, “who was unable to hold back… giving voice with tears… was the son-in-law of the Rebbe; precisely that quiet one with the silken sash, he first burst out crying… and all of honest heart followed him.”

For R. Menachem Mendel such an overt display of emotion was something of a rarity, for the most part it was precisely the quiet intensity of his inner-direction that made the deepest impression.7 But in Chabad, the eve of Rosh Hashanah has always been a time of particular seriousness, "He wanted none of the honors that belong to the Rebbe... I came to know truly that he doesn’t even entertain such a desire."a moment when the essential purpose of existence is lost, and needs to be vindicated and reclaimed.8 “We derived great pleasure and gratification,” wrote Altohoiz, “from the prayers of the son-in-law of the Rebbe... he prayed the evening prayer on the first night at great length, more than two and a half hours with many tears, and cries from the depth of his heart… Generally, his conduct on Rosh Hashanah was wondrous... He wanted none of the honors that belong to the Rebbe under any circumstances… heart to heart I spoke and pleaded with him… and I came to know truly that he doesn’t even entertain such a desire.”

Following Simchat Torah, Althoiz reported on R. Menachem Mendel’s whole hearted participation in the customary festivities: “He drank a lot, but with great humility and diffidence, without any pretension whatsoever, and he spoke a lot... words of chassidism mixed and peppered with midrash from the sages, with Kabbalah and numerical calculations (gematria)... all those gathered were greatly excited. The next day the words that he said, and his excellent qualities, were reported throughout the city…” Due to this report many more people gathered to celebrate with him on the following day. “How sweet and pleasant it was for me to see all the honor and splendor given to the Rebbe’s younger son-in-law…”

This pleasure, Althoiz lamented, would never be enjoyed by R. Yosef Yitzchak himself; only his absence had forced R. Menachem Mendel to fill the vacuum he left. R. Menachem Mendel’s naturally introverted inclination was overcome because responsibility to the community demanded he play a more public role. The tension between self and community, the Rebbe later taught, strikes an important balance. Without striving for personal improvement, you can never hope to influence others. Without the context of community, your individual qualities can never be maximized.9