via Lma’an Yisme’u
Reb Hillel Paritcher is one of the most well-known Chabad/Lubavtich chassidim of all time, the symbol of an oived, and a hallowed gaon and tzadik. Reb Hillel was a chossid of the 2nd Lubavitcher Rebbe Mitteler Rebbe and the 3rd Lubavitcher Rebbe the Tzemach Tzedek, and was appointed by the Mitteler Rebbe as mashpia for the Yidden living in the colonies. Reb Hillel reared many young chassidim according to the ways of Chassidus, and even taught and wrote unique teachings of Chassidus, some of which are printed in the sefer "Pelach Harimon." Reb Hillel passed away on the 11th of Av, תרכ"ד.
In his later years, the Tzemach Tzedek did not say Chassidus regularly. Once, a group of new chassidim came to Lubavitch and were disappointed that the Tzemach Tzedek was not saying maamorim. They complained to the Tzemach Tzedek that they came to hear Chassidus. The Rebbe told them they should go to Reb Hillel and he would teach them Chassidus. The chassidim complained, "A kli sheini cannot cook." (A borrowed term from Hilchos Shabbos, implying that learning Chassidus from Reb Hillel would not have the same "cooking effect" as hearing it directly from the source, the Rebbe himself.) The Rebbe replied, "But it is yad soledes bo." (Another borrowed term implying that the Chassidus of Reb Hillel was still boiling hot and would have an effect.)
Reb Hillel taught them the beginning of Tanya, and he prefaced it by saying, "Tanya discusses a Beinoni and a Tzaddik. A Beinoni is one who is of this world (since he is constantly challenged by the world around him). A Tzaddik is divested from this world (he is higher than this world and it has no affect on him). A Rebbe, however, is a greater level. He is divested from this world, yet is able to be in the world at the same time (he can live an ordinary lifestyle, though in truth he is totally above it all.)"