The sea was both a real danger to Galilean fishermen and a potent biblical symbol of forces no human ruler could master. Walking upon its surface intensifies the earlier storm-calming sign.
Matthew adds features that sharpen the Christological conclusion: Peter's attempt to come to Jesus, Jesus' rescue of him, the cessation of the wind, and the disciples' worship and confession.
Job 9:8 describes God as the one who alone stretches out the heavens and treads upon the waves of the sea. Psalms 77 and 107 similarly portray God's path through the waters and his sovereign control of the sea.
The imagery therefore does more than display miraculous power. Jesus is depicted performing an action embedded in Old Testament descriptions of YHWH's unique mastery of creation.
Jesus comes to the boat during the night walking on the sea. The terrified disciples think they see a ghost, but Jesus identifies himself and tells them not to fear. Peter comes toward him but begins to sink and cries for rescue; Jesus immediately saves him.
When Jesus and Peter enter the boat, the wind ceases. Matthew then records the disciples' response: they worship Jesus and confess, 'Truly you are the Son of God.' Action, scriptural imagery, worship, and confession converge in a single scene.
Neither a miracle nor the title 'Son of God' should be treated mechanically as proof of deity. The force of this passage comes from the combination of features Matthew deliberately brings together.
Jesus does what Israel's Scriptures poetically attribute to God, saves his disciple from the waters, receives worship, and is confessed as God's Son. The scene is therefore one of Matthew's strongest narrative presentations of Jesus' elevated identity.
The disciples worship Jesus and confess, 'Truly you are the Son of God.'