Verse 19 of chapter 1 is where the narrative proper begins in John’s Gospel. The first 18 verses function as a Prologue, introducing people and themes that will be addressed and expounded upon throughout the rest of the Gospel. And here in verse 19 is where John the Baptist’s testimony is picked up on and explained. In this short section (vv. 19-28) John provides his testimony to the Jewish leaders.
In verse 6 John the writer introduced us to John the Baptist as a man sent from God. His purpose was to be a witness, testifying to Jesus with the purpose that people would believe Jesus was the Messiah, the Son of God (v. 7). The content of John’s testimony was not given there. It was hinted at in verse 15 but now in verse 19 it will be given in more detail.
“And this is his testimony.” Jewish leaders sent priests and Levites from Jerusalem to John out in the wilderness on the other side of the Jordan in Bethany (vv. 19, 30). They wanted to know who this John was that was proclaiming a baptism of repentance. And so John’s testimony is initially given in the context of being questioned.
He is evidently asked if he is the Messiah, the Christ. But he responds that he is not.
If he is not the Messiah, then perhaps he is Elijah. He says he is not.
If he is not Elijah, then perhaps he is the promised prophet. He says he is not.
These three figures, the Messiah, Elijah, and the Prophet are all end time figures that in some way or other were expected by first century Jews. Some were looking for a Davidic Messiah, some a priestly one; some were looking for Elijah from Malachi 4:5 or the Prophet like Moses from Deut. 18:15-18 (Carson, The Gospel According to John, 142-43). But with three denials and no positive statement about his ministry the Jewish leaders are understandably not satisfied. They need a response to bring back with them to those who sent them (v. 22). So, they flat out ask, “What do you say about yourself?”
John responds in the words of Isaiah the prophet: “I am the voice crying out in the wilderness, make straight the way of the Lord” (v. 23). In the Isaiah text the ground is being levelled to make a way for the return of the exiles and the coming of the Lord and now John picks up this text to apply to his work of announcing the coming of the Messiah in Jesus.
This still leaves open in their mind why he baptizes if he is not the Messiah, Elijah, or the Prophet. What authority does he have to do this? The Pharisees among the group ask him this question and he responds by saying, “I baptize in water. Among you stands one you don’t know. He comes after me and I am not worthy to untie the thongs of his sandals.” This water baptism is a pointer to the one who comes after and is greater. Even untying his sandals, the job of a slave, is too much honour for John, he believes.
John’s testimony can be summed up as it was in the Prologue with inclusion from this section: to bear witness to the Light by being the voice in the desert.