What does the Bible say about the purpose of the Gospel of John?

The Gospel of John emphasizes faith as its primary purpose, stating that it was written to show that Jesus is the Christ, the Son of God, and that by believing in Him, one may have eternal life. John articulates this purpose directly in John 20:31, indicating that the accounts of Jesus' signs and teachings serve as evidences pointing to His divine nature and mission. The focus throughout the text revolves around the revelation of Christ's identity and work, not merely as historical facts but as vital teachings necessary for faith.