If we confess our sins, he is faithful and righteous to forgive us the sins, and to cleanse us from all unrighteousness.
If we confess our sins, God will then forgive the sins we confess and will, in addition, cleanse us from all unrighteousness. Consequently we do not need to worry that He has failed to forgive us for sins of which we are unaware! Sin incurs a debt to God, but forgiveness (Gr. aphiemi) cancels the debt and dismisses the charge. Sin also pollutes the sinner, but God’s cleansing (katharizo) removes the stain so we can be holy again. God absolutely promises forgiveness that is consistent with His justice (because Jesus Christ paid the penalty for all our sins).