Visualization of the Beis HaMikdash
The holy Beis HaMikdash was a microcosm of the universe. Therefore, every part of the Beis HaMikdash represented something that exists in the world. The Holy of Holies represented the very soul of man! This signifies that the human soul is supremely exalted and holy. Yet, the material aspect of man -- the body -- block the radiant light of the soul. Therefore, as long as the soul remains within the body, man has a diminished awareness of his exquisite holiness.
The powerful holiness of the Divine Presence dwelt within the Beis HaMikdash. Whomever entered the domain of the Beis HaMikdash was purified and elevated by the light of the Shechinah. He experienced the holiness and goodness of his soul. His elevated state inspired him to draw close to HaShem and serve Him through the fulfillment of the Mitzvos.
App: Imagine that the Beis HaMidash exists and the Shechinah dwells within her walls. Envision yourself entering into the holy Temple and the holy Shechinah purifies your heart and soul -- filling you with wisdom of HaShem, intense holiness, and true joy!
(Based on Mishnes Rebe Aaron, of Rav Aaron Cutler)