The Nativity of the Blessed Mother

R. This day was the Blessed Virgin Mary born of the lineage of David ; * The same is she through whom the salvation of the world hath been manifested before the eyes of all believers, and whose glorious life hath given light to the world.

V. With joy let us keep the Birth-day of the Blessed Virgin Mary.
Traditional Roman Breviary 

Today, September 8, we celebrate the Nativity of Our Blessed Mother, the Virgin Mary, the only person outside of her Divine Son who was born into this world without the stain of original sin.  From the time of her Immaculate Conception, Mary was formed and shaped to become the Ark of the Covenant, the one who would give birth to the Messiah.  She was born into a humble Jewish family and now reigns in heaven as Queen of heaven and earth, Queen of the Angels, who intercedes constantly for us before the throne of Her Son, our Lord and Saviour, Jesus Christ. 

There is a beautiful reading from St. Augustine in today's traditional breviary:

The Lesson is taken from a Sermon by St. Augustine the Bishop

Dearly beloved brethren, the day for which we have longed, the Feast-day of the Blessed and Worshipful and Alway-Virgin Mary, that day is come. Let our land laugh and sing with merriment, bathed in the glory of this great Virgin's rising. She is the flower of the fields on which the priceless lily of the valleys hath blossomed.

This is she whose delivery changed the nature that we draw from our first parents, and cleansed away their offence. At her that dolorous sentence which was pronounced over Eve ended its course ; to her it was never said : In sorrow thou shalt bring forth children. She brought forth a Child, even the Lord, but she brought him forth, not in sorrow, but in joy.

Eve wept, but Mary laughed. Eve's womb was big with tears, but Mary's womb was big with gladness. Eve gave birth to a sinner, but Mary gave birth to the sinless One. The mother of our race brought punishment into the world, but the Mother of our Lord brought salvation into the world.

Eve was the foundress of sin, but Mary was the foundress of righteousness. Eve welcomed death, but Mary helped in life. Eve smote, but Mary healed. For Eve's disobedience, Mary offered obedience ; and for Eve's unbelief, Mary offered faith.

Mary replacing Eve

Let Mary now make a loud noise upon the organ, and between its quick notes let the rattling of the Mother's timbrel be heard. Let the gladsome choirs sing with her, and their sweet hymns mingle with the changing musick. Hearken to what a song her timbrel will make accompaniment. She saith : My soul doth magnify the Lord, and my spirit hath rejoiced in God my Saviour. For he hath regarded the lowliness of his handmaiden, for, behold, from henceforth all generations shall call me blessed. For he that is Mighty hath magnified me. The new miracle of Mary's delivery hath effaced the curse of the frail backslider, and the singing of Mary hath silenced the wailing of Eve.