Teruma 5770: Why build the Mishkan?

This week, God tells Moses that the Israelites should bring free-will offerings of various precious raw materials to build the Mishkan, then proceeds to give rather detailed instructions on how to build not only the tent itself, but all of the utensils that go into it, including the ark, menorah and offering tables. This description is so long it will continue into next week's portion. Yet there is a nagging question: why do this? Torah gives a simple explanation, yet one that is somehow not satisfying:

8. And let them make me a sanctuary; that I may dwell among them.9. According to all that I show you, after the pattern of the tabernacle, and the pattern of all its utensils, so shall you make it.[Exodus 25]

The Simple explanation is that this is where God will dwell. Yet God is clearly omnipresent, even in one of God's many nicknames "the Place" HaMakom (המקום) do we find the idea of this. God is one place because God is all places. If God is all places, how could one place be more special than another? Some modern Jewish thinkers, as did Abraham Joshua Heschel in The Sabbath reject Judaism as a religion of place, but instead one of time. God is eternal too, but time is marked with reminders of specific dates which we use to remember events. Purim reminds is of the events of the book of Esther, Passover the Exodus from Egypt.
It's interesting to note something else: these are directions for the Mishkan, not the later Temple. Dimensions and other details are derived for the Temple from this text but God commands directions explicitly for the Mishkan, not the temple. Like we will read later in Exodus when Betzalel puts the Mishkan together, I Kings only chronicles the construction Solomon initiated four hundred and eighty years later. The Temple was wood and stone, a rather permanent structure. The Mishkan wasn't: it was cloth, poles and sockets and thus portable. Until the time of David and Solomon, it moved around. It was not stuck in one place.
Place, however is tangible -- time far from it. Even the things marked by time happen in a reference place. Yet this reference place itself is relative to the one observing by remembering that event. The Mishkan was there for every Shabbat, wherever it was in the wilderness or in the land of Israel. In ancient times, The Passover sacrifice could always be performed right at the Mishkan. With the destruction of the temple, as Resh Lakish, R. Johanan and R. Eleazar all said

While the Temple still stood, the altar used to make atonement for a man, but now that the Temple no longer stands a man's table makes atonement for him.[Ber 55a, Men 97a,Hag 27a]

The place of either the Mishkan altar or a dining room table changes depending on who is having an Erev Shabbat or Passover Seder. Places can act a reference to other things, even when place is not absolute.
I spent last weekend in a place where Sweetie once lived. She left this place to be with me. So we went back and visited -- and connected with friends. It was not a lot of spending time in place, but in relationship with people. It was activating memory for Sweetie, with every description of a place or an event at a street corner, shoreline or store. We even stopped in a few places of import to both of us: the breakfast restaurant she frequented every Saturday and the coffee shop she drank most of her caffeine in. Both places, during my visits to her became customary stops for both of us, cherished by both of us. To be there is to remember our other visits and the thing we ordered on their menus. It also is to be ready to go back for even more visits, to remember the past and make new memories.
The Mishkan is not about a place. It is about memory and relationship. Purim and Passover, for example are very different when celebrated in a group or alone. There is more meaning in the relationships generated at a synagogue Purimspiel than a private reading at home. A big Seder may be a lot of work and preparation, but it also is extremely rewarding in the relationships we strengthen at the Seder table. Each interaction creates new and precious memory.
God is infinite, yet finite amounts of God are in each of us. The Perkei Avot tells us

If three have eaten at one table, and speak there words of Torah, it is as if they had eaten at the table of HaMakom, Blessed be He, as it is said, "This is the table before the Lord" [Avot 3:3]

This and Avot 3:6 point to the idea of synthesis which brings God closer. The old joke about two Jews three opinions always make me think the third opinion is God's. The more people, the more we gain aspects of God, of HaMakom, in one place.
The Mishkan, as a temporary structure, was one that could and did move frequently. It was, most of all, a focal point. When encamped the people surrounded it. When marching its components were at the center of the ranks. When it was time to celebrate Passover, Shavuot, or Sukkot, everybody knew exactly where to assemble. The Mishkan was a place of assembly, and a place to get into relationship with everyone else. Within that relationship we gain memory, and revive memory of previous events. With those memories, we remember God, what God has done for us. We thus cause God to dwell with us and within us.