Rabbi Shemaryahu Gurary, also known by his Hebrew initials as Rashag, (1898-1989) was an Orthodox rabbi belonging to the Chabad-Lubavitch Hasidic movement. His father was Rabbi Menachem Mendel Gurary. He was the older son-in-law of Rabbi Yosef Yitzchok Schneersohn (1880- 1950), known as Rebbe Rayatz, the sixth Rebbe of the Chabad-Lubavitch Hasidic movement, and the brother-in-law of Rabbi Menachem Mendel Schneerson, the seventh Lubavitcher Rebbe. He worked with his father-in-law in communal service in both Russia and Poland and then arrived in the U.S. in 1940, where he continued this work until his death. Gurary had a comprehensive knowledge of Chassidic philosophy and was a devoted follower of his father-in-law Rabbi Yosef Yitzchak Schneersohn, and later of his brother-in-law, Rabbi Menachem Mendel Schneerson.
In 1931, Rabbi Yosef Yitzchok Schneersohn planned to expand the network of Chabad Yeshivas, known as Tomchei Temimim, in Vohlin, Ukraine. Rabbi Gurary travelled to investigate yeshivas in Vohlin and to found new yeshivas.
Upon the death of his father-in-law in 1950, he was considered to be a possible candidate to succeed him, but soon ceded his position to Rabbi Menachem Mendel. Rabbi Gurary himself understood that Rabbi Menachem Mendel was the legitimate spiritual heir to their father-in-law Rabbi Yosef Yitzchak, and that only he could actually fill the role.
Shemaryahu Gurary had one son, who was named Sholom Dovber and called Barry. He was born in Rostov-on-Don, Russia. on November 2, 1923, and died in Montclair, New Jersey, United States March 3, 2005. Barry Gurary was an ordained non-practicing Orthodox rabbi and physicist. He became the focus of disputes as an estranged relative to the Chabad-Lubavitch Hasidic dynasty.
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- Avrum M. Ehrlich, Messiah of Brooklyn: Understanding Lubavitch Hasidism Past and Present
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- Shaul Shimon Deutsch, Larger than Life