1 John 1:9 If we confess our sins, he is faithful and just to forgive us our sins and to cleanse us from all unrighteousness.
To think about it, confession is a single act. One in which we present ourselves, on faith, to God. He the chooses to do two things for our behalf, forgive our sin and a cleanse our soul. In our corruption, we fall short of what we were all intended to fully become. Having faith is to give to God a confession of sin that is wrapped in the hope of forgiveness and righteousness. Therefore, confession only works if we have faith in the process. Maybe that is why we confess so little and hold on to do many sins.