What is the relationship between John's work and the purpose of John's Gospel?
John 1:7 (ESV)
7He came as a witness, to bear witness about the light, that all might believe through him.
John’s witness was so that all men might believe in Jesus Christ. The Gospel According to John itself thus shares the same purpose as the ministry of John the Baptist (John 20:30–31)
7 He came as a witness, to bear witness about the light, that all might believe through him.