Disseminating the teachings of Chassidus abroad is not only a mitzvah which these times demand: it is an imperative. Moreover, as we can see for ourselves, it is a vital imperative, for upon it depends the actual, practical performance of the mitzvos, of which it is said,[233] "You shall be alive in them." The performance of the mitzvos depends on the dissemination of Chassidus especially in the present era, when the Divine light is obscured and concealed, and trials are rampant. 

Igros Kodesh (Letters) of the Rebbe Shlita, Vol. XVII, p. 264