But while the items individually represent G-d's forgiveness for various sins of the past, his promises for the future, and his protections for the present, the whole, the Mishkan itself, has an entirely different symbolism. It symbolizes not the parts, not the relationships within G-d's creation, but the very universal creation we experience itself (Bamidbar Rabbah, Tosafos).
The curtains above and below are the heaven and earth; the water is obviously the waters. The mizbeach haolah, the alter on which we sacrifice animals, represents those very animals, which G-d created so that they can serve their purpose. The mizbeach of the ketores represents the vegetation. The menorah is the lights of all the heavenly bodies, as well as the figurative light we can create ourselves in worship (Beraita de'Maasei).
|Love across generations|
In the whole Mishkan, all that was created was done exactly as G-d commanded, not as humans envisioned. Every part was geometric and exactly as it needed to be with one exception: the Keruvim of gold atop the aron. The Keruvim were in the form of an angelic boy and girl embracing each other. G-d told Moshe that from the time this was created and set atop the aron, his voice would emanate from the space between the two Keruvim. For this was the holiest spot of the whole Mishkan, indeed of the whole creation from that point on. Not because it was a solid piece of gold, not because the aron held a sefer Torah, not because the whole piece resembled heaven and earth and the angelic realm. Rather, the spot between the two figures can only represent absolute love of B'nai Yisroel one for another. Love, caring, support, all these platitudinous expressions we so easily throw around are truly G-d's greatest, most important messages to us and what He most wants from us.