The readings for the Baptism of our Lord are taken from Isaiah 42:1-9, Romans 6:1-11, and Matthew 3:13-17.
Central to the Epiphany season is the reminder that God has always had all people in mind and saves all people through the incarnation of His Son.
Isaiah foretold that the manner of Jesus was consistent with the good message of Jesus. He did not come to force His will or to destroy everyone who rebels against His will (all of us). Jesus spoke softly in out of the way places where He could be among the people—people that Jesus would help by His redeeming Word and Spirit.
Paulreveals in Romans that we are joined to Jesus through the good message so that everything of His becomes ours, just as Jesus fulfilled justice by taking upon Himself everything that was ours.
Matthew records how the divine nature of Jesus was revealed at His baptism: the heavens were opened, the voice of God the Father was heard, and the Holy Spirit appeared as a dove. The baptism of Jesus IS the baptism of us all, so by the grace of God, what was confirmed about Jesus has also been confirmed about us.