The book of Ezra says that upon the rebuilding of the Second Beit Hamikdash the old were mourning while the young were rejoicing (Ezra 3:10-13). The elders who had seen and experienced the superior spiritual nature of the First Beit Hamikdash cried when they saw the decline in the spiritual level of the Second Beit Hamikdash. But the young who had never seen the First Beit Hamikdash were rejoicing, not knowing the great spiritual decline of the new Beit Hamikdash. Our feeling toward the loss of the Beit Hamikdash today is in a way comparable to the feeling expressed by the young at the time of the rebuilding of the Second Beit Hamikdash. Just as the young didn't mourn because they didn’t know what they were missing from the First Beit Hamikdash, so too it is very hard for us to mourn for the Beit Hamikdash that we never knew. Since one reason for the inability to mourn the loss of the Beit Hamikdash is that we do not know what it is that we are missing, it is fitting for us to begin by intellectually understanding one basic function of the Beit Hamikdash, and use that as a stepping-stone to help us emotionally feel and mourn its loss.

The commentaries explain that even though Hashem fills the entire world, nevertheless there are times and places that enable us to experience Hashem’s providence more directly (Kad Hakemach “avel”). It was at Mount Sinai, during the Giving of the Torah, that Hashem 's presence was most intensely felt. All doubt disappeared once the Jewish People heard Hashem speak directly to them. This was indeed a truly awesome experience. The Ramban explains that the Mishkan (and later on the Beit Hamikdash) was meant to be a structure that held within it the revelation at Mount Sinai (Ramban on Shemot 25:1). Like Mount Sinai, the Beit Hamikdash was a place that enabled a glimpse into the spiritual world. It was a meeting place between the physical and spiritual. Therefore, anyone who visited the Beit Hamikdash was able to see first-hand that there is more to the physical world than meets the eye. From the ten miracles that constantly took place in the Beit Hamikdash, to the spiritual high that filled the air, a casual visit to the Beit Hamikdash was a rejuvenation of emuna (faith).

The Beit Hamikdash though didn’t only reveal spirituality in its structure. Rather, it took that spirituality and spread it out to the rest of the world as well. This is what the verse means when it says: "You shall build for me a Sanctuary and I will dwell in them." The Alshich points out that the verse does not say "I will dwell in it" but rather "I will dwell in them" to teach us that through the Mishkan (and later on the Beit Hamikdash) Hashem would dwell in the hearts of Klal Yisrael (Alshich on Shemot 25:8; Nefesh Hachaim 1:4 hagaha). In this sense, the Beit Hamikdash not only revealed the Providence of Hashem in its structure, but was also a conduit through which the existence of Hashem could be felt more directly in every place in the world.

We can now begin to at least touch the surface of one of many things that we lost with the destruction of the Beit Hamikdash. Without the Beit Hamikdash, which connected the spiritual and physical worlds, it is so hard to see beyond what meets the eye. It is hard to see the bond between the physical and spiritual. This is one of the reasons why the world today is so detached from spirituality while being deeply rooted in the physical. As the Gemara says: From the day the Beit Hamikdash was destroyed, a wall of iron separates between the Jewish People and their Father in the Heavens” (Berachot 32b).Chazal tell us that in every generation that the Beit Hamikdash is not rebuilt, it is as if it was destroyed in that generation (Yerushalmi, Yoma 1:1). By reflecting on the fact that it is our transgressions that yearly destroy this most holy place, we can perhaps begin to mourn on some level the huge loss of the Beit Hamikdash, and, through that, merit doing real teshuva and see the day of its rebuilding through the coming of the Mashiach speedily in our days.