In Orthodox practice, on the eve of the Nativity of the Lord, the liturgical services consist of the Royal Hours with the Typika, Vespers, and the Divine Liturgy of Saint Basil the Great. At Vigil in the evening, Great Compline is followed by Matins.
If the Nativity falls on Sunday, however, the Royal Hours with the Typika are read on the preceding Friday. On Friday evening, the office of the Forefeast, December 24. The Liturgy of Saint John Chrysostom is served on Saturday morning. At Vigil in the evening, Great Compline is followed by Matins. On Sunday morning, the Liturgy of Saint Basil is celebrated.
If the Nativity falls on a Monday, Royal Hours with the Typika are read on Friday December 22. On Saturday evening and Sunday morning we follow the order for the Sunday before the Nativity with the office of the Forefeast for December 24. On Sunday morning the Liturgy of Saint John Chrysostom is served. Vigil on Sunday evening consists of Great Compline is followed by Matins. On Monday morning the Liturgy of Saint Basil is celebrated.
On the eve of the Nativity, instead of three readings from the Old Testament at Vespers, there are eight readings (from Genesis, Numbers, Micah, Isaiah, Baruch, Daniel, and two more readings from Isaiah). The entrance is made with the Gospel.
At the end of Liturgy the priest places a lighted candle in a candlestick in the center of the church. Then the troparion and kontakion of the Feast are sung. At Vigil on the evening of the twenty-fourth, Great Compline is followed by Matins.
From the church hymns of this day:
"Behold the time of our salvation approaches, O Cave, prepare; the Virgin draws near to give birth". "Rejoice, O Virgin Theotokos, who of the Holy Spirit has borne Life to the world for the deliverance of all"; "the choir of angels honors you with hymns, O radiant Mother who has not known wedlock, and rejoicing it dances at your birth giving, O All Pure One; rejoice, Hope of the Orthodox, rejoice, Advocate of those who sing to you". "The Lord now draws nigh and comes, the expectation of the nations and the salvation of the world: O City of Bethlehem, prepare the cave, and you shepherds with the magi make haste". "He comes to shine the light without evening on those who before were in darkness and peril". "Rejoice all the earth, behold, Christ draws nigh being born in Bethlehem: O sea, be glad, O assembly of prophets, dance for joy, seeing today the realization of your words, and all you righteous, rejoice!" "Christ in strange wise comes to His own; let us become strangers to sin, and let us receive Him who dwells in the souls of the meek".
Apolytikion in the Fourth Tone
Mary was of David’s seed, so she went with Joseph to register in Bethlehem. She bore in her womb the Fruit not sown by man. The time for the birth was at hand. Since there was no room at the inn, the cave became a beautiful palace for the Queen. Christ is born, raising up the image that fell of old.
Kontakion in the Third Tone
Today the Virgin comes to the cave, to give birth to the Eternal Word. Hear the glad tidings and rejoice, O universe. Glorify with the angels and the shepherds the Eternal God, who is willing to appear as a little child.