Catechism of the Catholic Church

Jesus' public life begins with his baptism by John in the Jordan. John preaches "a baptism of repentance for the forgiveness of sins." A crowd of sinners-tax collectors and soldiers, Pharisees and Sadducees, and prostitutes-come to be baptized by him. "Then Jesus appears." The Baptist hesitates, but Jesus insists and receives baptism. Then the Holy Spirit, in the form of a dove, comes upon Jesus and a voice from heaven proclaims, "This is my beloved Son." This is the manifestation ("Epiphany") of Jesus as Messiah of Israel and Son of God. (719-720, 701, 438)