This is a vibrant sunrise over the Sea of Galilee, the very waters that Jesus walked upon and spent much of his ministry around. The quote is an abbreviated form of Matthew 14:30-33, in which the disciples witness Christ walking on the surface of the water.
This is one of the times in the Gospels where Jesus’ disciples mistake him for a ghost, a soul without a body. But they are witnessing Christ in his fullness, body and soul.
The quote focuses on the words of his disciples. Peter’s faith wavers and he calls out that he needs Christ. The disciples then recognize and profess Jesus as the Son of God.
But when [Peter] saw the wind, he was afraid, and beginning to sink he cried out, “Lord, save me.” Jesus immediately reached out his hand and caught him, saying to him, “O man of little faith, why did you doubt?” And when they got into the boat, the wind ceased. And those in the boat worshiped him, saying, “Truly you are the Son of God.”—Matthew 14:30-33 (RSVCE, emphasis added)