"When your wellsprings spread outward"
Shabbos & Yom Tov
In his letter to his brother-in-law Rav Gershon of Kitov, the Baal Shem Tov describes ascending on high on Rosh Hashanah and asking Moshiach, "When will the Master come?" The answer was that it would be when his teaching becomes known and revealed in the world and his wellsprings spread outward, so that others too could achieve the unifications he did. For Chassidim this became a mission: spreading the light of Chassidus hastens the Geulah.
Source: Iggeres HaKodesh of the Baal Shem Tov (printed in Ben Poras Yosef, 1781)