"Now John was clothed with camel’s hair, with a leather belt around his waist, and he ate locusts and wild honey. He proclaimed, ‘The one who is more powerful than I is coming after me; I am not worthy to stoop down and untie the thong of his sandals. I have baptized you with water; but he will baptize you with the Holy Spirit’" (Mark 1:6-8).
Mark was the first gospel written, and it has no nativity story, nor anything to say about the first 30 years of Jesus' life. It gets right to the heart of the story with this brief passage about John the Baptist, followed immediately by the arrival of the adult Jesus to be "baptized by John in the Jordan" (v.9).
The relationship between John and Jesus was a challenging one for Jesus' early followers. John the Baptist still had many followers, and it was apparently well-known that he had, in fact, baptized Jesus. So did that make him the master teacher and Jesus his disciple? The author of Mark solves the problem by having John himself acknowledge that someone 'more powerful' than he would be coming after him.
Metaphysically, John represents the highest level of spiritual realization we can achieve on our own, using our human intellect. His is a great accomplishment, as Jesus later recognizes. But Jesus represents a whole new level of awareness—one that comes from our intuitive spiritual Realization. It's helpful to refer to Matthew 11:11 (RSV)—"Truly, I say to you, among those born of women there has risen no one greater than John the Baptist; yet he who is least in the kingdom of heaven is greater than he." We may use our intellect and life experience to "rise" from our mortal limitations to a higher level of understanding. The Gospel of John has Jesus telling his followers (8:23, RSV): "You are from below, I AM from above." The full understanding and expression of the I AM—the Christ that is our true spiritual identity—cannot be learned. It requires a surrender to what is eternally the Truth of who we are. We are Spirit; we come from above, and everything else is illusion.