The baptism of the Lord was originally associated with Epiphany, but eventually it received its own feast day, the Sunday after January 6.
The baptism of Jesus is on his part the acceptance of his mission as God’s suffering Servant and he is submitting himself entirely to his Father’s will. He is numbered among sinners and as the Lamb of God, he takes away the sin of the world.
The Father’s voice responds to this acceptance and proclaims his delight in this Son, and the Spirit rests upon him. Jesus will be the surge of the Spirit for all mankind. At his baptism, the heavens are opened – the heavens that Adam’s sin had closed – and the waters are sanctified by the descent of Jesus and the Spirit, which is a prelude to the new creation.
The liturgy offers the gospel reading about the baptism of Jesus and the Preface sings about the revelation of the mystery of Jesus at Jordan.