Orthodox Churches that follow the revised Julian calendar are celebrating the Forefeast of the Nativity in preparation for Christmas. Here is Archimandrite Ephrem's translation of one of the hymns for Matins on the Sunday before the Feast of the Nativity:
Strange, wonderful and dread mysteries! The Lord of glory came to earth, and as a beggar in a cave he put on flesh, seeking to call back Adam, and to deliver Eve from her pains.
By your swaddling bands you loose the cords of offences, while by your poverty, O Compassionate, you make all rich. Laid in manger for unreasoning beasts, you free mortals from irrational wickedness, O Word of God ever without beginning.
I would encourage anyone who is interested in exploring the strange and wonderful mystery of the incarnation, which is the real "reason behind the season" to spend some time at Archimandrite Ephrem's page with his translations of the varied services for the Feast.