Today, September 8, we celebrate the great feast of the Birth of the Blessed Virgin Mary, whose glorious and pure life illumined all God's people.
The Church has celebrated the birth of the Holy Virgin since it's early centuries. A September birth was chosen because the Eastern Church begins it's Church year with September 1. The September 8 date helped determine the date for the feast of the Immaculate Conception on December 8 (nine months earlier).
Part of the tradition concerning Mary's birth, coming to us from the East, is that since she was created as the sinless Mother of God her mother gave birth to her after a perfect 9 month period. For this same reason, we celebrate the Annunciation of Our Lord on March 25 and the Nativity of Our Lord on December 25 – again, a perfect 9 month period.
Sacred Scripture does not give us any details concerning the Virgin Mary's birth. One early Church source, the apocryphal Protoevangelium of James, does give us some possible insight into this mystery. The work has no real historical value, but it does reflect the development of Christian piety in the early Church. According to this account, Anna and Joachim are not able to conceive but they do pray fervently for a child. Through their heartfelt prayer they receive the promise of a child that will advance God's plan of salvation for the whole world. This story (like many such stories in the Bible) stresses the special presence of God in Mary's life from the beginning.
St. Augustine relates the birth of the Virgin Mary directly to Our Lord's saving work. He tells all the earth to rejoice and shine forth in the light of her glorious birth. “She is the flower of the field from whom bloomed the precious lily of the valley. Through her birth the nature inherited from our first parents is changed.” The opening prayer at Mass speaks of the birth of Mary's Son as the dawn of our salvation and asks for an increase of peace.
Thy birth, O Virgin Mother of God,
heralded joy to all the world.
For from thou hast risen the Sun of justice,
Christ our God.
Destroying the curse, He gave blessing;
and damning death, He bestowed on us
Blessed art thou among women
and blessed is the fruit of thy womb.
For from thou hast risen of Sun of justice,
Christ our God.
– from The Divine Office – Matins (Morning Prayer)
Come, all you faithful, let us hasten to the Virgin: for long before her conception in the womb, the one who was to be born of the stem of Jesse was destined to be the Mother of God. The one who is the treasury of virginity, the flowering Rod of Aaron, the object of the prophecies, the child of Joachim and Anne, is born today and the world is renewed in her. Through her birth, she floods the church with her splendor. O holy Temple, Vessel of the Godhead, Model of virgins and Strength of kings: in you the wondrous union of the two natures of Christ was realized. We worship Him and glorify your most pure birth, and we magnify you.
– from the Byzantine Office of the Eastern churches