This letter was written in Tammuz 5688  less than a year following the Rebbe's release from soviet imprisonment and exile. At the time the Rebbe was living in Riga, Latvia. Click on images to enlarge:
Note: The 12th of Tammuz is the anniversary of the liberation of the sixth Lubavitcher Rebbe, Rabbi Yosef Yitzchak Schneersohn from his exile in Soviet Russia in 1927. The Rebbe was arrested in June of that year by agents of the Yevsektzia (the "Jewish Section" of the Communist party) and the GPU (forerunner of the KGB) because of his work to preserve Judaism throughout the Soviet Empire. The Rebbe was sentenced to death, for his "counter-revolutionary" activities, but a miraculous confluence of events forced the Soviets to commute it, and then to release him altogether.
The full account of the Rebbe's arrest and liberation can be found here.
The following is a translation of an excerpt from the Rebbe's diary (written several months before his arrest and printed as an appendix to "The Heroic Struggle"), in which he describes how (on an earlier occasion) he was saved by Divine Providence from the hands of four GPU thugs. While traveling by train to Moscow, in order to meet with various Rabbis and philanthropists to plan and budget further efforts for the upkeep of Yidishkeit in the face of soviet oppression, the Rebbe happened to meet a high ranking member of the Soviet Secret Police through whom his salvation would be effected mere days later.
The following is a letter written by the Lubavitcher Rebbe on the 3rd of Tammuz 5710  within a few months of the Friediker Rebbe's passing. Explanatory editions to the literal translation of the original text are enclosed in square brackets.
In the summer of (5543) 1783 the city of Minsk was the stage for a momentous meeting of minds. Orchestrated by Rabbi Shneur Zalman of Liadi – the Alter Rebbe and encouraged by the most influential Rabbinic authority of the time, Rabbi Eliyahu, the Vilna Gaon, “the great debate” attracted the greatest and most venerable Talmudic scholars of Lithuania, and was intended to resolve the ongoing conflict between the Chassidim and their opponents (“Misnagdim”).
After much deliberation the Goan Rabbi Eliyahu had decided that “if “the cult” [as the Chassidim where referred to] are to demand a debate then we are obligated to answer them”, and so Rabbi Schneur Zalman let it be known that he would be present in the city of Minsk on the Shabbos following the 9th of Av and would remain there for two or three weeks thereafter, so that he may answer “anyone with a query or a complaint against the Chassidim or their conduct”.