If we have committed sin, which is judged according to the light, and the sin is confessed, in that the will no longer takes part in the sin, He is faithful and just to forgive us, and to cleanse us from all sin. However, on the other hand if we say we have not sinned, it indicates that there is no truth in us, because we have no idea of reality – that is, the truth – and furthermore, we make God a liar, as He knows that all have sinned. If we make God a liar, his word cannot be in us. In summary: 1) we lie, 2) the truth is not in us and 3) we make God a liar. We require fellowship with God in the light, which in practical daily living, will enable us to connect to Him that forgives, for we will want to confess the sin the light has revealed. As John writes: But if we walk in the light as He is in the light, we have fellowship with one another, and the blood of Jesus Christ His Son cleanses us from all sin. (1 John 1:7 NKJV)