The Blessed Virgin Mary's birth is a cause for everyone and everything to rejoice, as it was a prelude to the birth of our Savior, Jesus Christ.
In the context of salvation history, there are many events that paved the way for the coming of the Messiah, Jesus Christ. One of the most essential, however, was the birth of his mother, the Blessed Virgin Mary.
God chose her as his earthly vessel to be made flesh and walk among us. Mary's birth helps prepare the way for the day when he would come into the world.
All creation rejoices
Mary's birthday is not only a day for all humanity, but also for the entirety of God's creation, to rejoice. It is a day that ushers in the final age of this world, foreshadowing how everything will be made new.
St. Andrew of Crete wrote about this reality in one of his discourses that is included in the Office of Readings:
Let all creation sing and dance and unite to make worthy contribution to the celebration of this day. Let there be one common festival for saints in heaven and men on earth. Let everything, mundane things and those above, join in festive celebration. Today this created world is raised to the dignity of a holy place for him who made all things. The creature is newly prepared to be a divine dwelling place for the Creator.
The Virgin Mary's birthday is a day when all created things can rejoice and give praise to God. He sanctifies even further the created world, dwelling within it as a part of creation.
St. Andrew of Crete further comments on how her birth is a prelude for what is about to come:
This radiant and manifest coming of God to men most certainly needed a joyful prelude to introduce the great gift of salvation to us. The present festival, the birth of the Mother of God, is the prelude, while the final act is the fore-ordained union of the Word with flesh. Today the Virgin is born, tended and formed and prepared for her role as Mother of God, who is the universal King of the ages.
The Nativity of the Blessed Virgin Mary is a beautiful feast, one that is not very often celebrated with great solemnity by Catholics in the West, but remains a potent reminder of God's gracious love and mercy.
