As they went away, Jesus began to speak to the crowds about John: "What did you go out into the wilderness to look at?  A reed shaken by the wind?  What then did you go out to see?  Someone dressed in soft robes?  Look, those who wear soft robes are in royal palaces.  What then did you go out to see?  A prophet?  Yes, I tell you, and more than a prophet.  This is the one about whom it is written, 'See, I am sending my messenger ahead of you, who will prepare your way before you.'  Truly I tell you, among those born of women no one has arisen greater than John the Baptist; yet the least in the kingdom of heaven is greater than he."

Matthew 11.1-6 provides the context for this passage.  Jesus has just finished giving his response to John's disciples who were sent by John to ask Jesus "Are you the one?"  No doubt the crowds hear or learn of Jesus' reply and wonder anew at who John the Baptist is.

Jesus asks "What were you expecting to see our there in the wilderness?"  Were you going to satisfy idle curiosity?  Did you think to find a madman or a great kingly leader?  In mercifully drawing the crowd to understand who John the Baptist is he is preparing them and helping them understand who he is.

For those who were genuinely expecting to find a prophet Jesus says "yes, he is a prophet and more."  What is more than a prophet to the Israelites?  The last of the prophets, the one directly preceding the Messiah.  Jesus quotes to them the Messianic prophecy of Malachi 3.1 and tells them it is fulfilled in John.  Of course in saying so Jesus proclaims himself as the Messiah, for the rest of the prophecy reads "And suddenly there will come to the temple the Lord whom you seek."