The Rebbe says:
1. There is a famous letter of the Baal Shem Tov in which he describes his encounter with the soul of Moshiach (the Messiah) during one of his journeys throughout the heavenly spheres. “When will the Master come?” asked the Baal Shem Tov, “When your wellsprings (the wellsprings of Chassidus) are spread throughout, even to the outside” answered Moshiach.
2. The Rebbe points out that since our Sages tell us that everything can be found in the Torah, this idea that as the result of the wellsprings of Chassidus being spread throughout the world Moshiach will come must also be hinted at in the Torah:
In its description of the exodus from Egypt, the Torah says, “The children of Israel left triumphantly”. The Targum Onkelos (a major translator of the Torah into Aramaic) translates this verse into Aramaic and writes, “The children of Israel left with their heads held high”.