Five of the books of the New Testament have traditionally been attributed to the apostle John, the son of Zebedee and brother of James. The gospel of John; 1, 2, 3 John; and Revelation. Most of the early church fathers claimed these books as written by John and the earliest copies have John listed in the title.
The works of John are connected by common themes and vocabulary. For example, there is a common emphasis on love, remaining in Christ, and the Light. Some have suggested that as much as 80 percent of the verses in 1 John reflect themes and ideas found in the gospel of John. There are also connections between 2 and 3 John. Take for instance the word “antichrist” found in these two books. The Greek word used for “antichrist” is only in these two books of the New Testament. Beyond that they also have similarities in structure, content, and the vocabulary used.
1 John was written by a man who had followed Jesus most of his adult life. As a young and brash man, he wanted to call down fire from heaven to destroy a whole town for rejecting Jesus (Luke 9:54) but with time and experience, he learned to live and love like Jesus. Now an old man, John being led by the Holy Spirit, writes these powerful letters (1, 2, and 3 John) helping us learn how to live for and love like Jesus.
This letter was written for a group of Christians who are troubled by false teachers whose behavior clearly showed them to be false disciples. John demonstrates for us how concern for correct doctrine, Christlike behavior, and love for God and others creates an environment where genuine fellowship can exist. He also shows us the importance of testing everything taught to us by comparing it to the revealed word of God. Apparently, these false teachers were denying that Jesus had come in the flesh (1 John 2:22; 4:1-2). They were boasting about being without sin (1 John 1:8, 10) and knew God even though their behavior proved otherwise (1 John 4:20).
4 themes stand out in 1 John: sin, false teachings, remaining in Christ, and eternal life. Each one teaches us powerful lessons about what it means to be a Christian and follow Jesus. Believes have been freed from sin through the work of Christ on the cross (1 John 5:1-4). We can reveal the truth about false teachers and their teachings by comparing it to God’s word (1 John 4:1-4). Those who remain in Christ are assured of their victory in Christ and show it through a sincere love for the Lord, their brothers and sisters, and their treatment of others. Eternal life with Jesus is the prize for all true believers and the one who has the Son has life (1 John 5:12).