The conclusion of the prologue (vv. 1-18) leads to the first of the two major sections of John’s Gospel, the Book of Signs. As the name suggests, the Book of Signs is characterized by seven major “signs” which establish Jesus’ deity and everlasting authority as the Son of God. The Book of Signs begins with the witness of John the Baptist and Jesus’ baptism. The Baptist’s significance has already been hinted at in the prologue. Now the pivotal nature of his ministry will become clear.
As already established in the prologue, the verb translated “bear witness,” and the noun “witness” or “testimony” will continue to be key words and concepts throughout John’s Gospel. It gives his gospel the flavor of courtroom testimony. John has no interest in telling tales. He is calling witnesses. He is presenting evidence.
Remember what John said his purpose in writing the Gospel was: “that you may believe that Jesus is the Christ, the Son of God, and that, by believing, you may have life in his name.” John is out to prove to anyone who will listen that Jesus is the Christ. What is more, John aims to persuade us to believe in Jesus, to trust him completely for salvation. And, John’s method of persuasion is “witness-bearing.” He is going to call a succession of witnesses who will testify that Jesus is the Lamb of God who takes away the sin of the world.