If we say that we have no sin, we deceive ourselves, and the truth is not in us.
and the truth is not in us: The Gnostics thought they had absolute truth in themselves; their knowledge was above even that of the apostles. John says that those who deny the presence of sin in their lives have no basis for claiming such elevated knowledge but, rather, do not even have the truth of God’s word in themselves. Instead of having truth in themselves, they may, as Lenski says, be "full of fictions, fables, myths, self-made fancies, notions that are not so" (392). The know-it-alls know little.