If the gospel stories were preserved in patterns determined by preaching and reinforced by decades of the same, we should expect the gospel sequences to be thematic, not chronological. And this is, in fact, what we find.
…Recalling the ancient tradition that Mark’s material came from Peter, we observe the graphic details indicating that this story represents firsthand testimony: the churning water, the dangerous wind, the peril of the little boat, and the growing anxiety of the crew.
…The question asked in the storm scene, therefore, represents the fundamental inquiry that brings individuals to faith in Jesus: “Who do you say that I am?” Here in the two sequential gospel scenes—the storm and the demoniac—we find that fundamental question stated and answered. It was a baptismal question. It is hardly surprising, therefore, that this question is answered at the waterside, the place immediately beside the baptismal waters. In Mark (especially), the waterside is a common site where potential believers encounter Jesus: the first disciples (Mark 1:16–19), Levi (2:13–14), the great crowds (3:7–9), the sick (6:53–55), the deaf mute (7:31–32), and the blind man (8:22). This suggestion of conversion and repentance at the waterside evokes the imagery of baptism.
…Does the juxtaposition of these two scenes—the storm and the demoniac—represent a preaching motif of early Christian preaching, a remnant of pre-baptismal catechesis, or does it simply mean the two events actually followed each other in sequence? It is difficult to say, but it is also unnecessary to decide.
From The Jesus We Missed: The Surprising Truth About the Humanity of Christ by Patrick Henry Reardon.