Theophany .............
is the Feast which reveals the Most Holy Trinity to the world through the Baptism of the Lord (Mt 3:13-17; Mk 1:9-11; Lk 3:21-22). God the Father spoke from Heaven about the Son, the Son was baptized by the St. John the Forerunner, and the Holy Spirit descended upon the Son in the form of a dove.
From ancient times this Feast was called the Day of Illumination and the Feast of Lights, since God is Light and has appeared to illumine "those who sat in darkness," and "in the region of the shadow of death" (Mt 4:16), and to save the fallen race of mankind by grace.
In the ancient Church it was the custom to baptize catechumens at the Vespers of Theophany, so that Baptism also is revealed as the spiritual illumination of mankind.
The origin of the Feast of Theophany goes back to Apostolic times, and it is mentioned in The Apostolic Constitutions (Book V:13).
Theophany in History
From the second century we have the testimony of St. Clement of Alexandria concerning the celebration of the Baptism of the Lord, and the night vigil before this Feast.
There is a third century dialogue about the services for Theophany between the holy martyr Hippolytus and St. Gregory the Wonderworker. In the following centuries, from the fourth to ninth century, all the great Fathers of the Church: Gregory the Theologian, John Chrysostom, Ambrose of Milan, John of Damascus, commented on the Feast of Theophany St. John of Damascus said that the Lord was baptized, not because He Himself had need for cleansing, but to reveal the mystery of the Holy Trinity, and finally, to sanctify "the nature of water" and to offer us the form and example of Baptism.
On the Feast of the Baptism of Christ, the Holy Church teaches us to confess and glorify the Holy Trinity, one in Essence and Indivisible. The Church also shows the necessity of Baptism for believers in Christ, and it inspires us with a sense of deep gratitude for the illumination and purification of our nature.