John the apostle, now in old age, is an influential leader among a network of churches around the city of Ephesus. This is likely where he had written his Gospel some years before, but in the meantime, some members of the Christian community have come to hold false beliefs, including a denial that Jesus was the Christ, the Son of God who came in the flesh and died for the forgiveness of sins. This led to a serious disagreement that resulted in those who held these false beliefs leaving their churches. This wasn’t the end of the story, however, because rather than holding these new beliefs privately, those who had left were actively trying to convince the Christians who remained to believe the same things through the influence of traveling preachers. Rather than naively accepting what these false teachers have to say, John encourages his readers to “test the spirits” to determine if the message they proclaim is from God, or a more sinister source.