Jesus, walking into the water, fully needing no baptism, marks that ritual as THE sign of initiation into the Christian walk, sanctifying and blessing the waters as the tool for his promise of salvation.
Soon, he will begin to teach the good news about God's kingdom, and then the long dark walk to Calvary.
Let us listen to the voice of the Father, sending down his Spirit in the form of a dove - This is my beloved son, in whom I am well pleased - and hearing it, be like John, knowing that we behold the Lamb of God who takes away the sins of the world. Then like Andrew, let us arise follow him!