Many scholars consider this section to be a second introduction to John’s Gospel, bringing the first section of a Heavenly view down to an earthly witness of the one sent to prepare the Messiah’s path. John the Baptist is the first witness of Jesus as the Christ, and his is the first testimony recorded. Witness or testimony is the clear theme of this passage, and in doing so, the Baptist has made a clear link between the Old Testament prophets and the appearance of Jesus on the scene; this is a theological foundation to Jesus’ later claims on this subject.
Verse 19 refers to “Jews of Jerusalem”, “priests” and “Levites”. These distinctions should be understood as referring first to what we might call the “powers that be” among the Jewish leadership of the time. The “priests” are those Temple functionaries who perform the duties of that office under the Law, and “Levites” refers to those from the same tribe who perform ancillary functions in the Temple, such as being ‘teachers of the Law” and Temple guards. This delegation was sent from the city to find out just who this crazy guy was who was dressing badly and baptizing people in the Jordan. John’s reply to all of their questions was “no”; he was not any of those…
So, if John wasn’t the Messiah, Elijah or the Prophet, then who was he and why was he making such a commotion?
John now identifies himself by quoting from Isaiah 40:3. John was God’s word spoken, not God’s word incarnate; John’s mission was to call for the people to prepare themselves for God’s arrival by repentance and baptism in water. He baptized in water to make preparation, but the One who was coming would baptize another way…
The next day John saw Jesus coming toward him and said, “Look, the Lamb of God, who takes away the sin of the world! This is the one I meant when I said, ‘A man who comes after me has surpassed me because he was before me.’ I myself did not know him, but the reason I came baptizing with water was that he might be revealed to Israel.”
“The next day” is not always understood the same way by scholars. Some maintain that it is a chronological reference, while others insist that in the Gospel of John it refers to the next significant event. In either case, after the Jewish delegation had left, at some point, John made his declaration that Jesus was the One for whom he had been preparing the way. He calls Jesus the “Lamb of God” making a clear reference to the sacrificial animal used in Temple sacrifices for the atonement of sin. Jesus would take sin away entirely, not merely making a temporary atonement as the lambs in the Temple did. John’s statement that he hadn’t known Jesus refers to John’s not understanding that Jesus, his cousin, was the One.
Then John gave this testimony: “I saw the Spirit come down from heaven as a dove and remain on him. And I myself did not know him, but the one who sent me to baptize with water told me, ‘The man on whom you see the Spirit come down and remain is the one who will baptize with the Holy Spirit.’ I have seen and I testify that this is God’s Chosen One.”
Here, John clearly tells the people how he knows Jesus is the One; John has seen the sign that God told him to watch for. Thus, because John has been made to see the Spirit of God descend upon Jesus ‘like a dove’ and then remain there, John states positively that Jesus is the Son of God.
Final Note: There is some dispute among scholars on the matter and timing of Jesus’ baptism by John. Note that in this text, John told the Jews that there was standing among them someone that they did not know (vv. 26-27). Of course this is one of the issues debated. It would appear that John had baptized Jesus at some point and then John had seen the spirit descend. Was it immediate or was there a lag in time? Verse 29 makes it appear that there was a time lag, even though John seemed to have suspected something the day before. Naturally, since the gospel of John is not synoptic, the fact that the Apostle doesn’t stick to a strict time-line can also muddy the waters a bit. Whatever the answer is, one thing is beyond debate: John, by a sign from God came to recognize that Jesus was the Christ and stated that fact boldly and publicly to the assembled people.