Thy Nativity, O Christ our God,
Has shown to the world the light of wisdom.
For by it those who worshipped the stars,
Were taught by a star to adore Thee,
The Sun of Righteousness.
And to know Thee the Orient from on high,
O Lord, Glory to Thee!
– Troparion for Christmas Day
The Christmas Liturgy begins with psalms of glorification and praise. The troparion and kontakion mark the entrance with the Book of the Gospels. The baptismal line from Galatians 3:27 once again replaces the Thrice-Holy. The Epistle reading is from Galatians:
But when the time had fully come, God sent forth his Son, born of a woman, born under the law, to redeem those who were under the law, so that we might receive adoption as sons. And because you are sons, God has sent the Spirit of his Son into our hearts, crying, “Abba! Father!” So through God, you are no longer a slave but a son, and if a son then an heir (Gal 4:4-7).
The Gospel reading is the familiar Christmas story from Matthew (2:1-12), and the liturgy continues in the normal fashion. A specific two-day celebration follows, dedicated to Mary the Theotokos and St Stephen, the First Martyr. The period of Christmas rejoicing extends to Epiphany during which time the Christmas songs are sung and fasting and kneeling in prayer are not called for by the Church.
The feast of Christmas is formally entitled the Nativity in the Flesh of our Lord and God and Saviour Jesus Christ. At Christmas we celebrate the birth as a man of the Son of God, the one who together with the Father and the Holy Spirit is truly God from all eternity. Thus, we sing in the Church.
Today the Virgin gives birth to the Transcendent One, and the earth offers a cave to the Unapproachable One! Angels, with shepherds, glorify Him! The wise men journey with the star! Since for our sake the Eternal God is born as a little child (Kontakion).
The feast of Christmas was not a separate Church feast for the first four centuries of Christian history. It was celebrated with Epiphany in the one great feast of God’s appearance on earth in the form of the human Messiah of Israel. The Nativity began to be celebrated as such on the twenty-fifth of December in order to offset the pagan festival of the Invincible Sun which occurred on that day. It was established by the Church quite consciously as an attempt to defeat the false religion of the heathens. Thus, we discover the troparion of the feast making a polemic against the worship of the sun and the stars and calling for the adoration of Christ, the True Sun of Righteousness (Mal 4:2), who is himself worshiped by all of the elements of nature.
Thy Nativity, O Christ our God, has shone to the world the light of wisdom! For by it, those who worshiped the stars were taught by a star to adore Thee, the Sun of Righteousness and to know Thee, the Orient from on high (Lk 1:78, translated as Dawn or Day spring). O Lord, glory to Thee! (Troparion).
Thus, the feast of Christmas is the celebration of the world’s salvation through the Son of God who became man for our sake that, through him, we might ourselves become divine, sons of God the Father by the indwelling of his Holy Spirit in us.