He said, "I am the voice of one crying in the wilderness, 'Make straight the way of the Lord,' as Isaiah the prophet said."
Previously the writer had mentioned that God had sent John the Baptist to bear witness concerning the light (John 1:6-8). He also mentioned what John had said about Jesus, namely, that Jesus had a higher rank than he did (John 1:15). Now the evangelist explained John the Baptist’s witness in more detail.