The world is passing away with its lusts, but he who does God's will remains forever.

 This leads John to his last point in this section. He writes to them, not because they did not know the truth, but because they did. Westcott puts it in this way: "The object of the apostle in writing was not to communicate fresh knowledge, but to bring into active and decisive use the knowledge which his readers already possessed." The greatest Christian defence is simply to remember what we know. What we need is not new truth, but that the truth which we already know become active and effective in our lives. 