One of the distinct features of John’s writing style was his habit of noting both sides of a conflict. He wrote to show the difference between real Christianity and anything else. Here are some of his favorite contrasts.
| Contrast between | Passage |
| Light and darkness | 1:5 |
| The new commandment and the old commandment | 2:7, 8 |
| Loving the Father and loving the world | 2:15, 16 |
| Christ and Antichrist | 2:18, 22 |
| Truth and lies | 2:20, 21 |
| Children of God and children of the devil | 3:1-10 |
| Eternal life and eternal death | 3:14 |
| Love and hatred | 3:15, 16 |
| True prophecy and false prophecy | 4:1-3 |
| Love and fear | 4:18, 19 |
| Having life and not having life | 5:11, 12 |