these 2 verSes, below, of the torah (bible) encompasses the fundamental reason for building the holy temple.

It is THE physical entity, the ark of the holy covenant,  that is the basis for the jewish nation, containing the  "aseret hadibrot" and is to have a place in the world as well as a dwelling place for the l-ord to reside amongst mankind.

the rest is commentary, how to and details.


Exodus Chapter 25 (Shemos, Terumoh, Rishon, Cohen reading)
.ח. וְעָשׂוּ לִי, מִקְדָּשׁ; וְשָׁכַנְתִּי, בְּתוֹכָם.

8. And let them make Me a sanctuary, that I may dwell among them. 



Leviticus Chapter 26
(Vayikro, Bechukosie, Sheini, Levite reading)
.יב .וְהִתְהַלַּכְתִּי, בְּתוֹכְכֶם, וְהָיִיתִי לָכֶם, לֵאלֹהִים
וְאַתֶּם, תִּהְיוּ-לִי לְעָם. 

12. And I will walk among you, and will be your God, and ye shall be My people.