On September 8 we celebrate the Feast of the Nativity of the Theotokos – the birthday of the mother of Jesus.
“The fact that there is no Biblical verification of the facts of Mary’s birth is incidental to the meaning of the feast. Even if the actual background of the event as celebrated in the Church is questionable from an historical point of view, the divine meaning of it ‘For us men and for our salvation’ is obvious. There had to be one born of human flesh and blood who would be spiritually capable of being the other of Christ, and she herself had to be born into the world of persons who were spiritually capable of being her parents.
The feast of the Nativity of the Theotokos, therefore, is a glorification of Mary’s birth, of Mary herself and of her righteous parents. It is a celebration as well of the very first preparation of the salvation of the world. For the ‘Vessel of Light,’ the ‘Book of the Word of Life,’ the ‘Door to the Orient,’ the ‘Throne of Wisdom’ is being prepared on earth by God himself in the birth of the holy girl-child Mary.” (Thomas Hopko, The Orthodox Faith, Vol. 2, Worship, p. 132).