Sometimes the old way we use to do things can be blended with a new way of doing something or with a new idea, producing a better idea, etc. But that is not the case when it comes to salvation. People used to think that we would be justified based on our strict adherence to the law, but that is not the case and that is an idea that does not mix with Jesus proclamation that salvation is free, apart from works of the law. It’d be like pouring new wine into old wineskins.