BESURAS HAGEULO
It may be added, that this concept is also alluded to in the name of "Beis Rabbeinu" in our generation:
"Rabbeinu" [our Rebbe] - His two names alluded to the Redemption: His first name - Yosef - "And it shall come to pass that on that day, the L-rd shall continue to apply [yoseef] His hand a second time to acquire the rest of His people that will remain from Assyria and Egypt, etc. and from the islands of the sea, etc, and He shall gather [Asaf] the lost of Israel and the scattered ones of Judah He shall gather from the four corners of the earth."
His second name - Yitzchak - refers to the laughter and rejoicing that will be complete in the future Redemption, and which will be completed through our righteous Moshiach. Thus it is written, "Then our mouths will be filled with laughter [S'chok]. It specifies 'then,' in the future, when they will say to Yitzchak (specifically), 'Because you are our father.'"
And Beis (Rabbeinu) [The House of our Rebbe] - its number is seven hundred seventy.
The name by which "Beis Rabbeinu" is called by all Jews has been universally accepted to be this number, and completed. Through the elevation of the lowest possible place all the other lands of the nations are also elevated.
References
15. As is well-known, the name indicates the content and nature of the thing called with that name (Tanya, "Shaar HaYichud v'HaEmunah," end of chapter 1. See at length Teshuvos u'Be'urim (Kehos, 5734), section 1 and the cross references there).
16. Yeshayahu 11:11-12.
17. Tehillim 126:2.
18. Which is not the case during the time of exile, when "it is forbidden for an individual to be completely joyful [literally, fill his mouth with laughter] in this world, since it is written that 'Then our mouths will be filled with laughter [we will be completely joyful]'" (Brochos 31a).
19. Yeshayahu 63:16. Shabbos 89b.
20. One should note the customs of the leaders of the Jewish people, who learned allusions and lessons in Divine service from secular matters as well (for example, the number of wagons in the train, which is incidental, and all the more mentioned above).
