From the Rebbe’s explanation:
– The entire order of spiritual worlds is based on a flow of influence from a giver (a higher realm of existence) to a recipient (a lower realm of existence). Thus, through uniting a mashpia with a mekabel, one brings about unity and a state of completeness in the entire spiritual cosmos, transforming our world, the lowest of all worlds and redeeming it entirely from a state of need.
This is related to the concept of the seven days of Sukkot paralleling “the seven days of Creation” and thus, including the entire order of spiritual worlds. It also relates to the mitzvah of sukkah which is representative of “the sukkot” in which “I (haShem) caused the children of Israel to dwell”. Our Sages explain that these sukkot refer to the “Clouds of Glory” which accompanied the Jews on their journey through the desert.
Clouds come from the evaporation of water from the earth and then, bring rain to the earth.
This relates to the service of Tishrei which represents “an arousal from below” (to quote a verse from the Book of Breishit: “… a mist arose from the earth.”) Through the service of elevating the earthly aspects of our existence, we refine the entire realm of worldly existence and then draw down Divine influence into the world, transforming the nature of its existence…
Through the service described above, the “Clouds of Glory” become united with the simple booths in which we live…
The above concept is also related to Chapter Haazinu which is always read in the month of Tishrei. This chapter begins with the words: “Give ear heavens… earth, hear!”. This is interpreted by our Sages to indicate how Moshe was “close to heaven and far from the earth.”
This potential is granted to every Jew. Even within his worldly concerns, he has the potential to be “close to the Heaven,” and reveal “Heaven” within “earth,” fusing the two into a single identity.
(Based on the Rebbe’s talk on the 4th Night of Sukkos, 5750)