Nativity of the Theotokos
The Nativity of the Theotokos is one of the Great Feasts of the Orthodox Church, celebrated on September 8 (For churches still using the old Julian Calendar - for liturgical purposes - September 8 falls on September 21 of the Gregorian Calendar. In other words, "Old Calendar" Churches, such as the Russian Orthodox Church, still celebrate the Nativity of the Theotokos on the 8th, but the day is actually the 21st according to the everyday calendar that is used in society at large).
The Holy Virgin and Theotokos Mary was born to elderly and previously barren parents by the names of Joachim and Anna, in answer to their prayers. Orthodox Christians do not hold to the Roman Catholic doctrine of the Immaculate Conception of Mary, in which it is supposed that Mary was preserved from the ancestral sin that befalls us all as descendents of Adam and Eve, in anticipation of her giving birth to the sinless Christ. The Orthodox believe that Mary indeed received the ancestral sin, having been conceived in the normal way of humanity, and thus needed salvation like all mankind. Orthodox thought does vary on whether Mary actually ever sinned, though there is general agreement that she was cleansed from sin at the Annunciation.
On the eve of the feast, Vespers is served and contains three Old Testament readings that have New Testament meaning. In Genesis 28:10-17, Jacob's Ladder which unites heaven and earth points to the union of God with men which is realized most fully and perfectly in Mary the bearer of God. "How awesome is this place! This is none other than the house of God, and this is the gate of heaven!" In Ezekiel 43:27-44:4, the vision of the temple with the door to the East perpetually closed and filled with the glory of the Lord, symbolizes Mary. And in Proverbs 9:1-11, Mary is also identified with the "house" which the Divine Wisdom has built for herself.
Sometimes Matins is served on the morning of the feast. The Gospel reading is from Luke 1:39-49, 56. It is read on all feasts of the Theotokos and includes the Theotokos' saying: "My soul magnifies the Lord and my spirit rejoices in God my Saviour, for he has regarded the low estate of his handmaiden, for behold, henceforth all generations will call me blessed."
Divine Liturgy is served on the day on the feast. The epistle reading is from Philippians 2:5-11, and speaks of "Christ Jesus, who, being in the form of God, did not consider it robbery to be equal with God, but made Himself of no reputation, taking the form of a bondservant, and coming in the likeness of men." The gospel reading is taken from Luke 10:38-42 and 11:27-28 together; this reading is also always read on all feasts of the Theotokos. In it, the Lord says, "blessed are those who hear the word of God and keep it!"