9  If we [freely] admit that we have sinned {and} confess our sins, He is faithful and just (true to His own nature and promises) and will forgive our sins [dismiss our lawlessness] and [continuously] cleanse us from all unrighteousness [everything not in conformity to His will in purpose, thought, and action].

 

10  If we say (claim) we have not sinned, we contradict His Word {and} make Him out to be false {and} a liar, and His Word is not in us [the divine message of the Gospel is not in our hearts].