Rashi notes the redundancy of the word Mishkan. He explains that the two words allude to the Mishkanos, which were taken from us. In a play on words, the letters of mishkan can also be read as mashkon, collateral. Chazal intimate that the two Batei Mikdash are collateral for the sins committed by the nation, and Hashem took them from us until that time that we repent and deserve its return. The obvious question is: It was the Bais HaMikdash that was destroyed, not the Mishkan. It is related that Horav A. Mishkovsky, zl, explained that, in the Bais HaMikdash, there were two kedushos, areas of consecration. These were the bayis and keilim, edifice with its vessels; and the makom, place/area which the Mishkan occupied. When the Bais HaMikdash was destroyed, only the edifice and its utensils lost their sanctity. The kedushas makom ha’mikdash continued. The Mishkan, however, which did not have a set place since it was always on the move, maintained only kedushah. Thus, the redundancy of the word mishkan alludes to the mishkan aspect of the Bais HaMikdash. The area of commonality the Bais HaMikdash shared with the Mishkan was twice taken from us, when the edifice and its contents were destroyed.
In an alternate approach, Horav Chaim Brisker, zl, cites the Navi Yeshayahu (1:27), Tzion b’mishpat tipadeh v’shaveha bitzedakah; “Tzion will be redeemed through justice, and those who return to her through righteousness.” Why concerning Tzion does the Navi use the word mishpat, justice, and regarding shavehah, the returnees, tzedakah, righteousness? When a lender absolves the borrower of the loan – he benefits and the areiv, guarantor, also gains. The difference is that the borrower saved money. The guarantor, however, was only spared the headache of having to repay the loan in the event the borrower defaulted on the loan. Thus, even though the loan has been cancelled, the guarantor really did not receive any benefit from the lender.
The Mishkan/ Bais HaMikdash was collateral for our “loan,” our good behavior and worthiness to be called Am Hashem, Nation of G-d. When Hashem takes pity on His people and absolves them of their sins, the collateral nature of the Bais Hamikdash ends. Since the “loan” was absolved through atonement, there is no longer room for arvus. The forgiveness obligates and is the precursor for the rebuilding of the Bais HaMikdash.
This is how to understand the pasuk and the distinction between mishpat and tzedakah. Forgiving the sins of the Jewish people is tzedakah, “righteousness” on the part of Hashem. Once they had been absolved and had achieved atonement however, it is only mishpat, justice, that now the Bais HaMikdash should be rebuilt. We repented, we returned, now we deserve the Bais HaMikdash. There are two aspects to Mishkan: tzedakah and mishpat. We were welcomed home. At this point, we warranted the rebuilding of the Bais HaMikdash.
