According to the mystical teachings of the Zohar

According to the mystical teachings of the Zohar, heavenly "ushpizin"
(guests) visit the suka on the festival of Sukot. They are: Abraham, Isaac, Jacob, Moses, Aaron, Joseph and David. Each day, one of these righteous people is the "main" guest who brings the others along. On the first night of Sukot, the "main" ushpiz is Abraham.

Our ancestor Abraham was renowned for his outstanding "hachnasat orchim"
(hospitality). In fact, the Talmud derives from Abraham that "Having guests is greater than greeting the Divine Presence." (The Torah relates that when G-d visited Abraham after his brit mila (circumcision), he hastened to usher into his tent what he thought were mortal guests but were really angels.) If this was how Abraham acted before the Torah was given, pursuing even those who appeared as "Arabs who bow down to the dust of their feet" as guests, how much more so must we strive to emulate his hospitality after the Giving of the Torah and with regard to our fellow Jews.

In truth, the concept of hospitality is a very good description of our Divine service in exile, when the entire Jewish people is likened to a "guest." Our Sages characterized the exile as a period in which the Jews are like "children who have been exiled from their Father's table." The rightful and natural place of a Jew is at G-d's "table"; during the exile he is not in his natural "habitat," and is therefore a "guest" in alien territory.

Why would G-d create such an unnatural situation? Because of the special quality and advantage of the Jews' Divine service during the exile. This service is so important and beloved to G-d that He was willing to transform His children into "guests."

Our Sages said: "G-d did Israel a favor ('tzedaka,' from the root meaning righteousness) that He scattered them among the nations." The true reason for the Diaspora was not punishment, but "tzedaka" - to fulfill a positive purpose and objective. G-d wanted the Jews to imbue every location on earth with holiness as preparation for the Messianic era, when the entire world will be His "dwelling place."

The Baal Shem Tov (who is also the "Chasidic ushpiz" on the first night of Sukot) said something similar on the verse in Psalms, "The steps of man are ordered by G-d," explaining that wherever a Jew finds himself, he should know that it is not "by coincidence," but that G-d has deliberately led him there for a Divine purpose.

It is precisely through our service in exile that we will merit to "greet the Divine Presence" in the fullest sense with the Final Redemption, when "the glory of the L-rd will be revealed," with happiness and gladness of heart.

Adapted from Vol. 29 of Likutei Sichot