In what does Mary's greatness lie? Why do "all generations call her blessed?" Why is Mary the central figure during this season of Advent?
Essentially, Mary's greatness lies in her total and unconditional submission to God's will; she is the "perfect disciple" - which is what holiness is all about. The holiness of Jesus lay in "doing always the things that pleased His Father."
Besides, during this beautiful season of Advent, Mary teaches us two important lessons by her own example of her visit to the house of Elizabeth. She teaches us to wait in hope and trust in the mercy and goodness of God; and she teaches us to give, as she gave, of all she had and all she was.
Mary's waiting reminds us that waiting in hope for God's gift makes us special in His eyes. She teaches us too that Christmas is not primarily getting (which seems to be an obsession today!), but it's about giving, and letting go, so that Christ can come and save the world.
Lord, I wait for Your help, and in Your word I trust. I wait for You, O Lord, more eagerly than watchmen wait for daybreak. (Ps. 130:5-6).