At the time John wrote this epistle, false teachers had arisen from among the church. Some people were teaching that Jesus wasn’t human, denying that He was the true Messiah. The Christian Church was spreading throughout the Roman Empire, and those who were eye-witnesses to the earthly ministry of Christ were dying (either from old age or from martyrdom). So false teaching was ripe for having a devastating effect.
Plus these teachers claimed to be Christians, which would have been very troubling for the young churches to hear. Whom can they believe, and how can they evaluate new teachers as they come?
But John knows the truth, and so he writes a letter to help the church know how to tell the children of God from the impostors. John combats false teaching with absolutes: truth and lies, light and darkness, love and hate, sin and righteousness, Christ and antichrist. He shows the church how to tell if they are children of God and how to tell if a teacher is trying to deceive them.
John’s letter moves around from theme to theme, but he makes three things very clear to the church:
- The children of God believe in Jesus Christ
- The children of God keep His commandments
- The children of God love one another