In 1972, a Soviet Jewish systems engineer named Yitzchak Kogan found out that the technology he was working on was being shipped to Egypt and Syria. Unable to stomach the idea of aiding the Jewish state’s enemies, he applied for permission to leave for Israel. Although fourteen years elapsed before he and his wife obtained exit visas, they were immediately fired from the jobs. The two returned to Russia in 1991, just five years after gaining their freedom, and Kogan became the rabbi of a Moscow synagogue, and remains active in Jewish communal and religious life.
From his childhood on, Kogan—known among Chabad Ḥasidim as the tsaddik (righteous man) of Leningrad—obtained a Jewish education and observed Jewish practices in defiance of the regime, and sometimes at great personal risk. Dovid Margolin writes:
As soon as Kogan began attending Soviet public school, his parents hired the first of a string of m’lamdim, Jewish religious teachers, to come to their home. . . . It was not only what the old men taught Kogan that he absorbed, but what they left unsaid. Each of them, without exception, had suffered for his beliefs at the hands of the Communist regime. [One] teacher, Rabbi Berel Medalia, was the son of Rabbi Shmarya Leib Medalia, a Lubavitcher Ḥasid who served as chief rabbi of Moscow before being arrested and executed by Stalin in 1938; three of Rabbi Shmarya Leib’s sons were likewise arrested. Berel Medalia served something like a decade in the Gulag system. . . . Despite everything, in addition to teaching children like the Kogans, over the years Medalia became a quiet Jewish influence on many young refuseniks.
As Kogan’s bar mitzvah approached in the summer of 1959, his mother feared the ceremony would summon unwanted interest from the authorities, and turned to the recently released [from imprisonment] Rabbi Moshe Mordechai Epstein for advice. Epstein instructed her to hold the bar mitzvah in a small summer vacation town outside Leningrad. “He also said that Papa shouldn’t be there,” Kogan explains. “Instead of my father, Rabbi Epstein made the Barukh she-p’tarani [the blessing a father recites at his sons’ bar mitzvah].”
Kogan would later train to be a ritual slaughterer, in order to provide Leningrad’s Jews with kosher meat, and served as a sort of unofficial rabbi for his fellow refuseniks:
Among the many young Jewish refuseniks who credit the Kogans’ assistance on their path to Judaism were Lev and Marina Furman, who first connected with them in 1974. They would recall joining about 50 others at the Kogans’ apartment for their first kosher Passover seder. Other communal activities at the Kogan home included Hebrew and Jewish study circles and Purim shpils.
Read more on Chabad.org: https://www.chabad.org/news/article_cdo/aid/5387559/jewish/The-Tzaddik-of-Leningrad-Looks-Back-30-Years-After-the-Fall-of-the-USSR.htm