The Seder is the only one of the 613 mitzvot that is performed specifically at night, for on Passover, we turn the darkness into light. Song is the expression of an excited soul. It is the way to break out of oneself and reach for freedom. Every synagogue in the world faces Jerusalem. The Talmud says creation began in Jerusalem, and the world radiated outward from this spot.
Medieval maps show Jerusalem at the epicenter of Asia, Europe, and Africa.
The world flows into this place, and all of life's forces resonate there. From Jerusalem, the whole world is cast into perspective. Jerusalem is a vision of God in our lives, a metaphor of a perfected world. Jerusalem gives us hope to achieve what we as a people must do, to sanctify this world. When we finally were redeemed, it happened so quickly and hastily that even then we were unable to grasp its full significance.