The Feast of Epiphany is today, Jan 6th, and it is upon us. It is also celebrated as a Holy Day of obligation in many European countries and certainly in the various Byzantine and Eastern Rites, known in the latter as Theophany.
One emphasizes the visit of the Three Magi to the Baby Jesus in Bethlehem, the latter celebrates the manifestation of Christ to the world with His baptism in the Jordan by St John the Baptist, the Forerunner.
Let the great Dominican theologian of the early 20th century explain the Epiphany:
The Feast of the Epiphany is the continuation of the mystery of Christmas; but it appears on the Calendar of the Church with its own special character. Its very name, which signifies Manifestation, implies that it celebrates the apparition of God to his creatures…
At Divine Liturgy today, the Byzantine Rites bless the “Jordan water” which is then taken home for personal use as a sacramental, much as the Roman Rite does at the Easter Vigil.
Matthew 3:13-17 – Then Jesus came from Galilee to the Jordan to John, to be baptized by him. John would have prevented him, saying, “I need to be baptized by you, and do you come to me?” But Jesus answered him, “Let it be so now; for thus it is fitting for us to fulfill all righteousness.” Then he consented. And when Jesus was baptized, he went up immediately from the water, and behold, the heavens were opened and he saw the Spirit of God descending like a dove, and alighting on him; and lo, a voice from heaven, saying, “This is my beloved Son, with whom I am well pleased.” (RSV)
Lamb and Redeemer – John’s baptism was looking toward repentance. Its purpose was to bring hearers to the point of experiencing conviction for their offenses. John, however, did not want anyone to draw the conclusion that Jesus himself also came to the Jordan to repent of his sins. So he sets this point straight from the outset by calling him both Lamb and Redeemer of all the sin that is in the world. He who is able to take away the sins of the whole world was himself without sin. (St. John Chrysostom, Commentary on Matthew)