The answer is: Isaiah

Isa 40:3

The Gospel of Mark kicks off with an intriguing shout-out to one of the Bible's major voices: Isaiah. He’s the first prophet we encounter, and compellingly, it's a prophecy pointing towards the preparation for the coming of Jesus—“A voice cries out: ‘In the wilderness prepare the way of the Lord.’” What a dramatic entrance!

Interestingly, Isaiah lived during a time of significant upheaval, much like the turbulent world Mark wrote into. The quote comes from what’s often called the Book of Consolation, highlighting a theme of hope emerging from a desolate environment, resonating with anyone who feels lost. It's akin to marching bands heralding a parade—it reveals that something monumental is about to unfold.

Also, Mark colossally diminishes the grandeur traditionally ascribed to baptism by framing John the Baptist—who himself alludes back to wanting nothing but skin-deep service—instead of flashy displays. A technique like this is wrapped in the irony of musical theatre: the first prophets setting the stage for a one-of-a-kind show.

Fun fact: Mark’s usage of the wilderness isn't merely a geographical reference, but rich with theological meaning! The wilderness has been a transformative space for many throughout biblical narratives, from the Israelites' journey to John’s prophetic echo. It’s that reminder that paths of transformation often tread through trials and sacrificial encounters—a motif alive throughout scripture!