Although I am less than the least of all God's people, this grace was given me: to preach to the Gentiles the unsearchable riches of Christ, and to make plain to everyone the administration of this mystery, which for ages past was kept hidden in God, who created all things. His intent was that now, through the church, the manifold wisdom of God should be made known to the rulers and authorities in the heavenly realms.Dearest Brothers and Sisters: With today's first Sunday of Advent, a new liturgical year begins. The Church takes up her journey again, and invites us to reflect more intensely on the mystery of Christ, a mystery that is always new and that time cannot exhaust. Christ is the Alpha and Omega, the beginning and the end. Thanks to Him, the history of humanity proceeds as a pilgrimage toward the fulfillment of the Kingdom which he inaugurated with His Incarnation and victory over sin and death.
~John Paul II, Angelus address, December 2, 2001
From Advent and Christmas Widsom from Pope John Paul II
I think mystery is a good way to approach Advent. To see God and His salvation through the eyes of a newborn child is a challenge that is especially difficult in these modern cynical times. During Advent, we are called to search for God anew and make room for Him in our hearts.