The feast of the Annunciation is one of the twelve great feasts of the Church. It commemorates and celebrates the event described in the Gospel according to St. Luke (1:26-38):
And in the sixth month the angel Gabriel was sent from God unto a city of Galilee, named Nazareth, to a virgin espoused to a man whose name was Joseph, of the house of David; and the virgin's name was Mary. And the angel came in unto her, and said, Hail, thou that art highly favoured, the Lord is with thee: blessed art thou among women. And when she saw him, she was troubled at his saying, and cast in her mind what manner of salutation this should be. And the angel said unto her, Fear not, Mary: for thou hast found favour with God. And, behold, thou shalt conceive in thy womb, and bring forth a son, and shalt call his name Jesus. He shall be great, and shall be called the Son of the Highest: and the Lord God shall give unto him the throne of his father David: And he shall reign over the house of Jacob for ever; and of his kingdom there shall be no end. Then said Mary unto the angel, How shall this be, seeing I know not a man? And the angel answered and said unto her, The Holy Ghost shall come upon thee, and the power of the Highest shall overshadow thee: therefore also that holy thing which shall be born of thee shall be called the Son of God. And, behold, thy cousin Elisabeth, she hath also conceived a son in her old age: and this is the sixth month with her, who was called barren. For with God nothing shall be impossible. And Mary said, Behold the handmaid of the Lord; be it unto me according to thy word. And the angel departed from her.
The services for the feast of the Annunciation present a broad and profound exegesis of the Gospel reading on the annunciation of the Archangel Gabriel to the Virgin Mary before she conceived the incarnate Logos in her most pure womb. The stichera and canon for the feast explain the Archangel’s greeting to the Most Holy Theotokos and her answer to this greeting (Lk. 1:26-38). Thanks to this exegesis the entire mystery and meaning of this event is presented to the faithful in all its universal significance.
For ancient Christians this feast had various names: The Conception of Christ, the Annunciation of Christ, the Beginning of Redemption, or the Annunciation of the Angel to Mary. Only in the seventh century, in both the East and the West, the name, Annunciation of the Most Holy Theotokos, became generally accepted.
This feast was established in deep antiquity. We know of its celebration from as early as the third century (see the homily by St. Gregory the Wonderworker on that day). In his conversations, St. John Chrysostom and Blessed Augustine mentioned this feast as being an ancient and customary celebration. During the course of the fifth to eighth centuries, after the appearance of heresies that degraded the person of the Mother of God, the feast was especially rendered honor in the Church. In the eighth century, St. John Damascene and St. Theophan, Metropolitan of Nicea, composed the festal canon that is now sung in the Church.