This letter was written by John, the son of Zebedee, who was one of Jesus’s first twelve disciples recruited in 27AD (see Matthew 10:2). It was written between c.86 and 88AD, after the writing of John’s Gospel in c.85AD and before the Revelation of John in c.90AD.
By the time he wrote this letter, John was an old man in his late seventies who addressed his readers in Ephesus and elsewhere as ‘my dear children’ (see 1 John 2:1). It was about sixty years since he had witnessed the events of Jesus’s life (see 1 John 1:1) but only a short time since he had written about them more fully in the Gospel of John. It’s not surprising therefore that, in his letters and his gospel, John often uses similar words and expressions – compare, for example, 1 John 1:1-2 with John 1:1-2, and 1 John 1:6-7 with John 3:19-21.
St John's Church, Ephesus
The letter was written by John to warn believers of a dangerous heresy that was starting to engulf the churches in the Roman province of Asia (see Map 29). Those spreading this heresy – known today as ‘Gnostics’ – believed that Jesus was truly divine, but argued that he could not be fully human. Some taught that Jesus only seemed to have a human body, while others said that the divine Christ only joined the human Jesus at baptism and left before he died (a view still held by some sects today). John set out to convince the readers of his gospel and the recipients of his letters that Jesus was indeed both fully human and fully divine.