Permanent Mikdash

Rashi says that the repetition of the word mishkan hints to the destruction of the Temple and the need for it to be inaugurated again in the future.  Why at the inauguration ceremony of the mikdash would we speak of the destruction of the mikdash?  The Rebbe (Likutay Sichos volume 11) explains that the point is the opposite.  The mikdash will be permanent, it is the sins of the people that will lead to its destruction, but the building itself has an eternal power.  Even in its destruction because of an outside factor of sins, it is merely פקודי המשכן, it is a pikadon in the hands of Hashem, but we will get it back.  The power of the mikdash is eternal, it is only temporarily concealed.

What is the symbol that the mikdash is always present?  The Rambam in the 4^th Ch. Of Beis Habechirah brings the whole story of the ark being hidden in the ground.  The achronim ask why does the Rambam cite this, what halacha is to be learnt out from it?  The Rambam writes in the first Ch. That the vessels of the mikdash are part of the mikdash itself.  A mikdash without the כלי מקדש is a lack in the mikdash.  Therefore, the Rambam was bothered how could the second Temple be lacking the ark, it would be an incomplete mikdash?  The Rambam answers that Shlomo originally made a place for the aron to be placed under ground.  See the Rogatchover on the last possuk of the haftorah (Ashkenazic custom) ואשים שם מקום לארון means Shlomo made a place for the aron to be placed underground.   Therefore, when the aron was there it was considered to be in its place and there was nothing lacking from the mikdash.  The Rambam supports this idea that underground is considered the place of the aron and not just a measurement taken for security purposes by citing how Yosheyahu Hamelech hid it even before there was any danger present (Sichos on Hilchos Beis Habechirah.) 

Just as the aron remains in its place, it is just hidden, so too the mikdash is a pikadon that merely needs to be reconstituted.  However, the basis of mikdash, the symbol of the presence of the Shechinah resting there, the aron is always there and remains the same for all of the Battei Mikdash.