This letter was written between 85-90 AD. It has two main purposes: First to encourage its readers to live in fellowship with God and with his Son, Jesus Christ, and, second to warn them against following false teaching that would destroy this fellowship. This teaching was based on the belief that evil results from contact with the physical world and so Jesus, the Son of God, could not really have been a human being. Those teachers claimed that to be saved was to be set free from concern with life in this world. They also taught that salvation had nothing to do with matters of morality or of love for others.
In opposition to this teaching, the writer clearly states that Jesus Christ was a real human being, and he emphasizes that all who believe in Jesus and love God must also love one another.