John 1:19-34 [RSV] Here is a compilation of verbatim phrases and sentences copied from these verses. This is a personal study method of identifying an important part of each verse and then letting them guide what I write.
19 the testimony of John
Who are you?
20 He confessed, he did not deny
I am not the Christ.
21Are you Eli′jah?”
He said, “I am not.”
“Are you the prophet?”
he answered, “No.”
22 What do you say about yourself?
23 I am the voice of one crying in the wilderness,
24 they [priests and Levites] had been sent from the Pharisees
25 why are you baptizing, if you are neither the Christ, nor Eli′jah, nor the prophet?”
26 among you stands one whom you do not know,
27 he who comes after me
28 This took place in Bethany
29 Behold, the Lamb of God, who takes away the sin of the world!
31 I myself did not know him
32 And John bore witness,
“I saw the Spirit descend and it remained on him
33 I myself did not know him
He on whom you see the Spirit descend and remain
this is he who baptizes with the Holy Spirit.
34 I have seen and have borne witness
this is the Son of God.” 
This is the kickoff week of the ”public” ministry of Jesus. It must have been like drawing the short straw for the priests and Levites that were sent to that wild place to question John. He could read between the lines; he knew their question “who are you?” was code for “do you claim to be yet another messiah?” It’s interesting to think about John’s courage implied by this phrase, “he confessed, he did not deny.” There were many false messianic claims and that phrase was a critical part of his answer, “I am not the Christ.” Perhaps the most dangerous part of his ministry was the act of baptism itself. John had just identified himself as “the voice of one crying in the wilderness” telling God’s chosen people they weren’t clean enough. There was something more they needed to do: to be cleansed by baptism in preparation for the coming of the Messiah, just as if they were the same as an impure Gentile.
John resisted identifying his own activity with anything [or anyone] other that what he’d just seen with his own eyes: “Behold, the Lamb of God, who takes away the sin of the world!” Twice John uses the odd phrase “I myself did not know him” but we know he did know WHO Jesus was. His confession was that now he recognized WHAT Jesus was, and that confirmed his own identity. “For this I came baptizing with water, that he [Jesus] might be revealed to Israel.”
He had become a disciple! “And John bore witness, I saw the Spirit descend as a dove from heaven, and it remained on him…He on whom you see the Spirit descend and remain, this is He who baptizes with the Holy Spirit.” What he’d witnessed with his own eyes was the work of the Holy Spirit. He could personally confess to the reality of that work as the truth of his own testimony: “this is the Son of God.”
Disciple: a personal follower
Witness: personal observation
Confession: personal knowledge
Testimony: the confession of a follower from personal knowledge
Read and Ponder - Faith in Daily Life 