"Therefore many other signs Jesus also performed in the presence of the disciples, which are not written in this book; but these have been written so that you may believe
that Jesus is the Christ, the Son of God;
and that believing you may have life in His name."
The gospel of John is written with one purpose: to show the deity of Christ. John begins with the work and characteristics of the Son of God before the incarnation. He tells us “the Word was God” (John 1:1), he repeatedly calls Jesus the “Son of God” and “Lord and...God” (John 20:28). In John's gospel, Jesus also affirms His deity. In John 8:58 He says “...before Abraham was, I Am” (God called Himself "I Am" in Exodus 3:14). But John also emphasizes Jesus' humanity, challenging the error of a religious sect of his day, the Gnostics, who did not believe in Christ’s humanity. John clearly shows that Jesus not only claimed to be the Christ (the Messiah), the Son of God, but by the many miraculous signs He performed He proved it. The last and greatest of these signs was His resurrection from the dead. John is telling us that God has provided only one way for us to be saved, and that is by believing in Jesus as the Christ, the Son of God. And by believing this we have the gift of eternal life. "And there is salvation in no one else; for there is no other name under heaven that has been given among men by which we must be saved." (Acts 4:12)