John 1:19-23

And this is the testimony of John, when the Jews sent priests and Levites from Jerusalem to ask him, “Who are you?” He confessed, and did not deny, but confessed, “I am not the Christ.” And they asked him, “What then? Are you Elijah?” He said, “I am not.” “Are you the Prophet?” And he answered, “No.” So they said to him, “Who are you? We need to give an answer to those who sent us. What do you say about yourself?” He said, “I am the voice of one crying out in the wilderness, ‘Make straight the way of the Lord,’ as the prophet Isaiah said.”

John 1:19-23

So far, John the Baptist has been mentioned twice.  First, we are told that "he cam as a witness, to bear witness about the light".  As we already know, the light is Jesus.  Second, we are told that "John bore witness about him".  "Him" is once again referring to Jesus.

Now, John the Baptist is brought up again and we are told about "the testimony of John".  I'm assuming that he's referring to John the Baptist since he goes on to talk about him.  It can be confusing since the author of this book is John and he share his name with John the Baptist.  You can see that AMP takes this stance as they add his full name in square quotes: "This is the testimony of John [the Baptist]".

John the Baptist must have been doing something to cause a ruckus because we now find Jews sending priests and Levites to ask him directly "who are you?".  John the Baptist makes it clear who he is by saying, "I am not the Christ".  They obviously thought him to be someone of importance, guessing that he was Elijah or the Prophet.

Actually, we read from the other gospels that John the Baptist was in fact Elijah who they were expecting.  Upon further research, I found that they were expecting Elijah reincarnated in the flesh, but John the Baptist denied this because he was instead like Elijah and not Elijah himself.

In any case, John was clear in saying that he was not the Christ, nor Elijah, nor the Prophet.  So they ask John the Baptist to give them an answer so they can answer those who sent them.  Who is John the Baptist?  His answer comes from Isaiah and he says "I am the voice of one crying out in the wilderness, ‘Make straight the way of the Lord,’ as the prophet Isaiah said."  Well, John the Baptist does live in the wilderness and he is telling people get to get right with God.