Introduction:
John, often referred to as the Apostle John, is a central figure in the New Testament and one of the twelve apostles of Jesus Christ. He is traditionally credited with the authorship of the Gospel of John, three Epistles (1 John, 2 John, 3 John), and the Book of Revelation. Known for his close relationship with Jesus, John is often identified as "the disciple whom Jesus loved" (John 13:23).

Background and Early Life:
John was the son of Zebedee and Salome and the brother of James, another of Jesus' apostles. The family was likely of some means, as Zebedee owned a fishing business on the Sea of Galilee. John and James were initially disciples of John the Baptist before following Jesus (John 1:35-40). They were part of Jesus' inner circle, along with Peter, witnessing significant events such as the Transfiguration (Matthew 17:1-2).

Ministry with Jesus:
John's close relationship with Jesus is evident throughout the Gospels. He was present at key moments, including the raising of Jairus' daughter (Mark 5:37) and Jesus' agony in the Garden of Gethsemane (Mark 14:33). John and his brother James were nicknamed "Boanerges," meaning "Sons of Thunder," possibly reflecting their zealous nature (Mark 3:17).

Role in the Early Church:
After Jesus' resurrection and ascension, John became a prominent leader in the early Christian church. He was present at Pentecost when the Holy Spirit descended upon the apostles (Acts 2:1-4). John, alongside Peter, played a crucial role in the spread of the Gospel, performing miracles and preaching boldly (Acts 3:1-10).

Writings:
1. The Gospel of John: This Gospel is distinct from the Synoptic Gospels (Matthew, Mark, and Luke) and emphasizes the divinity of Christ. It begins with the profound theological statement, "In the beginning was the Word, and the Word was with God, and the Word was God" (John 1:1). The Gospel of John includes unique accounts such as the conversation with Nicodemus (John 3:1-21) and the raising of Lazarus (John 11:1-44).

2. The Epistles of John: These letters address themes of love, truth, and fellowship with God. In 1 John, he writes, "God is love, and whoever abides in love abides in God, and God in him" (1 John 4:16). The epistles emphasize the importance of living in the light and rejecting false teachings.

3. The Book of Revelation: Written during John's exile on the island of Patmos, Revelation is a prophetic and apocalyptic text. It contains visions of the end times, the return of Christ, and the ultimate victory of good over evil. John writes, "Blessed is the one who reads aloud the words of this prophecy, and blessed are those who hear and obey what is written in it" (Revelation 1:3).

Later Life and Legacy:
Tradition holds that John lived to an old age, possibly being the only apostle to die of natural causes. He is believed to have spent his later years in Ephesus, where he continued to teach and guide the early Christian community. His writings have had a profound impact on Christian theology, particularly concerning the nature of Christ and the concept of love.

John's legacy is one of deep spiritual insight and unwavering commitment to the truth of the Gospel. His contributions to the New Testament continue to inspire and guide Christians around the world.