Tuesday Sivan 5, Erev Shavuot, 49th day of the omer 5703
Torah lessons: Chumash: Nasso, Shlishi with Rashi.
Tehillim: 29-34.
Tanya: And this is (p. 279)...BLESSED AND EXALTED. (p. 281).

On the eve of Shavuot 5557 (1797) the Alter Rebbe taught:

Sanctify them today and tomorrow and they shall cleanse their garments.1 "Sanctify them today and tomorrow," is done from Above, but "they shall cleanse their garments" - one must do himself. This was the entire teaching.

The Tzemach Tzedek elaborated: "Sanctify them" was said by G‑d to Moshe. The extension of Moshe is in every generation2 and they3 are able to sanctify the "today" and the "tomorrow"; but for this is needed "..and they shall cleanse their garments" - the garments of thought, speech and deed. This must be done by each person on his own.