This week's Torah reading introduces a series of five parshiyot whose central theme is the commandment to build a Mikdash, a place for the resting of the Divine Presence. As Rambam (Hilchot Beit HaBechirah) indicates, this was not only a hora'at sha'ah, a temporary enactment for the duration of the Jews' sojourn in the Desert, but also a mitzva l'dorot, a commandment for all times which was later fulfilled by the building of the mishkan Shiloh, the two Batei HaMikdash in Jerusalem and finally to be fulfilled by the building of the third Beit HaMikdash bimheira b'yameinu. As Ramban (Introduction to Chumash Sh'mos) and Rambam (Hilchot M'lachim Chapter 11) note, the building of such a "dwelling-place" for the Shechina is one of the quintessential components of ge'ulah (redemption).
Many commentaries note the textual anomaly inherent in the phrase "v'asu li Mikdash v'shachanti b'tocham" -- "and they shall make for me a Mikdash and I shall dwell in them" (25:8) rather than "b'tocho", "in it" (the Mikdash). The goal of Mikdash is the resting of the Shechina in each and every member of B'nei Yisrael, not just in one geographical location. The Shechina's presence seen by all in the Mikdash served as a potent reminder of the goal of Creation: Hashem's permeation of the entirety of Creation and especially Man, the pinnacle of Creation.
Rashi (Ki Tissa 31:18) maintains that although Hashem's command to Moshe to build the Mishkan appears in the Torah before the Cheit HaEigel (sin of the Golden Calf), chronologically it was given after. One interpretation of this Rashi is that the donation of the material for and the construction of the Mishkan served as an atonement for the sin. (Ramban (beginning of Teruma), however, disputes Rashi's position and maintains that although Moshe did not tell the B'nei Yisrael about the Mishkan until after the Cheit and the subsequent period of atonement culminating on Yom HaKippurim, Hashem commanded him concerning its construction beforehand.) Based on the idea developed above that the true place of hashra'at haShechina is in each member of Klal Yisrael, some have suggested in explanation of Rashi's position that before the Cheit HaEigel, there was no need for the Mishkan. The level attained by B'nei Yisrael at Ma'amad Har Sinai was so exalted that each Jew was fit to serve as a Mishkan. Only after the sin, when the spiritual level of Klal Yisrael declined was there a need for a structure to serve as a place for the Divine presence to rest amongst the Jewish people but not in them. The Mishkan would serve also as a physical example of that which should be re-attained by each Jew. (Also see Meshech Chochma (beginning of VaYakheil) for a somewhat different analysis based on the same premise and his proposed halachic difference between the two periods with reference to the construction of the Mishkan.)
Malbim develops this idea further and sees within the very structure of the Mishkan a parallel to the human body. The Aron and the Torah within it symbolize the head and brain, the seat of the intellect; the Kodesh together with the Menorah and Shulchan represent the life center of Man, the lungs and the heart enclosed by the rib cage symbolized by the k'rashim. (See Malbim's commentary for additional parallels.) Thus, the physical, structural Mishkan directly symbolized the ultimate Mishkan: within Man.
One would expect that during the time period of the ultimate redemption, one characterized by Rambam as a time period of the widespread pursuit of the knowledge of G-d (Hilchot M'lachim 12:4-5) and by the prophecy of Yeshaya (11:9) "ki mal'a ha'aretz dei'a es Hashem kamayim layam m'chasim" -- "for the Earth will be filled with the knowledge of G-d as the waters cover the seabed" that there would be no need for a physical Mikdash since then K'lal Yisrael themselves would serve as the makom hashra'at haShechina parallel to the approach proposed above concerning the pre-Cheit HaEigel era. On a simple plane, the above analysis only applies to the Mishkan in the Desert. The Beit HaMikdash on Har HaMoriyah, the place from which the entire Earth was created (see Massechet Sukka on the meaning of Even Shetiya), would always be a unique place for the Divine Presence even when K'lal Yisrael would be worthy themselves of this distinction. However, Malbim on the passages in Yechezkel (37:27, 28) "v'hayah mishkani aleihem" -- "and my dwelling will be on them" followed by "v'yad'u hagoyim ki ani Hashem m'kadeish et Yisrael bi'h'yot mikdashi b'tocham l'olam" -- "and the Nations shall know that I am G-d, the Sanctifier of Israel, when my Mikdash is amongst them forever" interprets that whereas the true place of the Shechina would be the b'nei Yisrael themselves, as indicated by "aleihem", the physical Mikdash referred to by "b'tocham", would serve as an external reminder to the entire world as to the unique relationship of G-d to the bearers of His Word throughout history.
Viewing oneself as the ultimate dwelling-place of the Shechina should be highly motivating in one's 'Avodat Hashem. In the words of the Kotzker Rebbe, "Where is Hashem's Shechina? Wherever He is allowed to enter!" This should also fill us with anticipation for the fulfillment of the prophecy of Yechezkel "v'hayah mishkani aleihem v'hayiti lahem lailokim!" (See Nefesh HaChayim (Sha'ar 1) for a further development of the themes presented here.)