Both the devil and the sinner disobey God; the devil insists on his disobedience, while the sinner does not insist on his sin (when he admits his mistake and asks forgiveness from God.)
If the sinner insists on his sin, or says the sin is good or justifiable, then he is a devil.
....while a sinner will almost be forgiven if he asks forgiveness and turns to God in repentance, vowing that he will not repeat his disobedience once again.
If beef were butter and butter were beef, what would beef be?
The Catholics have this thing called confession - pretty much works the same way. Thing is, you can just keep on sinning your heart out and all is good after a trip to the confessional.
Who are you planning to ambush from behind?