"With the destruction of the second Temple, G‑d changed His mode of interaction with the universe. Until the destruction, the Temple was the window to G‑d; spirituality had a physical home in Jerusalem.
With the destruction, G‑d temporarily removed the Temple from its geographic location and placed it within us. Instead of traveling to Jerusalem, G‑d wanted us to find Him in our inner Jerusalem. Now, our bodies are our Temples, our souls are our windows, our minds are our kohanim and our animal instincts are our sacrifices. We cannot offer physical sacrifices three times a day, but we can pray three times a day. We cannot attend Temple services three times a day, but we can tap into our souls three times a day. We cannot atone for our shortcomings by sacrificing animals, but we can sacrifice our inner animals—our hormones, our lusts, our desires, our beastly compulsions. We cannot find G‑d in Jerusalem; we must find Him in us.
If the times of the Temple were principally G‑d reaching down to His world, then the times of our exile are us reaching up, from within that world.
This is G‑d’s master plan. First, a sweeping, dramatic outdoor concert of public spirituality, reaching viscerally and tangibly into the everyday, physical reality. Then He exchanges this for an internal, personal, private experience, forcing us to reach up to find Him, bringing the entire Creation along with us. Together, the two experiences lay the groundwork for the third and final Temple—an age that will synthesize both directions of spirituality. An age of where G‑d’s presence inside our hearts and minds and in the physical world is internalized to achieve a whole new reality: the era of Moshiach."
- from www. Chabad.org