John wrote this letter to awaken his readers to the dangers posed by certain ideas and practices which could weaken, or possibly destroy, the Christian faith. The primary practice that John appears to refute is Gnosticism.
Gnosticism was one of the most powerful heresies of this age. Some examples of what Gnostics believed are:
- That one isn't saved by faith alone
- That the world is evil
- That God, as creator of the world, is evil
- That all matter is evil
- That Satan was good because he offered Eve the fruit from the Tree of Knowledge
- Knowledge is the saving gnosis
- Certain people were given divine knowledge which would allow them to escape this godless world (These were the aristocratics)