It is incmubent upon us to bring the message of Love and Awe of God to our brothers and sisters, all of mankind.
When we read in the Book of Lamentations (attributed to the prophet Jeremiah) about the conquest of Judea by Nebuchadnezzar, we cry over the terrible suffering during the siege and afterwards – rape and pillage, and the destruction of Jerusalem. Very little is written about the Temple itself: Gentiles entered the holy areas of the Temple, where Jews are not permitted to enter [a phrase in 1,10]; in Lamentations 2,7 Jeremiah mentions the Altar and the Temple, together with the walls of the castles; in 2,20 Jeremiah laments the killing of "priests and prophets in the Temple of God". From the wording of this phrase it seems that the priests and the prophets are not the same – and if not, what were the prophets doing in the Temple? So in these verses, it seems that the word Temple is used metaphorically, referring to Jerusalem as a whole. Jerusalem and Zion are referred to explicitly 21 times.
The main effect of the fall of Jerusalem, the Capital of Judea, was the loss of sovereignty. Thus it is fairly clear that the lamentation over the Temple is secondary to the lamentation over the people and the sovereignty and is not specifically over the service in the Temple or over the building itself, despite the fact that Jeremiah himself was a priest!
The three prophets Jeremiah [7,4 etc.], Isaiah [1,11 etc.] and Ezekiel [8 etc.] sharply criticized the way people related to the services in the Temple, or the way they behaved in the Temple itself!
It is written, "The Temple in Jerusalem was not destroyed UNTIL AFTER the Temple in Heaven had been destroyed." This can be understood as follows: It is not possible to really understand the Temple service in Jerusalem. We DO understand that the Temple service establishes a relationship with "Heaven". The "Temple in Heaven" is a reflection of our relationship with the Almighty. Our sages tell us that there is no value in a Temple on earth if our relationship with the Almighty is not based on Love and Awe of God but rather on technicalities of the Temple service and on sacrifices meant to atone for sins which continue even after the sacrifices are brought.
It is incmubent upon us (collective humanity) to mend our ways – not necessarily each individual person. I personally know many people, Noahides, Muslims, Christians and Jews, who have a perfect Love and Awe of God, but before it is possible to build a Temple it is necessary for collective humanity to have the proper relationship with God. It is our responsibility to teach, to show, to demonstrate in action and behavior the Love and Awe we have of God, and to try in every way to bring the message to our brothers and sisters, all of mankind, under God. By doing so we will be preparing the way for the Messiah!