A 569-570). He is banished by Domitian to the penal island of Patmos AD 95 (Rev 1:9-11). He is set free upon the accession of Nerva: probably returns to Ephesus of Nerva and there writes his Gospel and the three letters. He knew this area well; his message was directed and was meant to counter the Gnostic false teachings.
Gnosticism was one of the most dangerous heresies of the first two centuries of the church. This was the time part of which John lived. Gnostics central teaching was that salvation is a product of knowledge. The Gnostic theory held that good and evil were necessary counterparts of each other and that both strung from the same divine source-God.
This letter was probably addressed to the church in Ephesus because John in his later years resided there. John was reflecting in his old age that God is light (1 John 1:5), God is love (1 John 4: 16), the son of God came in flesh and was the Messiah (1 John 4:2).

Literary Context
One of the most notable qualities of light is its power to dispel darkness. On the highest moral, the spiritual, God exhibits this quality in a superlative degree-the darkness of sin cannot exist in His sight. At the slightest hint that God could have the slightest of darkness, John comes out blazing truth that in Him is no darkness at all. Literary darkness in Him is not, not (one darkness). Come to me all you who are weary and burdened, and I will give you rest (Matthews 11:28) seems to say bring all your dirty laundry, or bring your lives so cast in darkness and Jesus, who has the ultimate of light will bloat all into purified light unimaginable. Nothing can flourish in darkness except certain low forms of life that tend to make the darkness more repulsive. Decay progresses rapidly in the absence of life giving light. Eyes that have grown...