Works are the outward manifestation of inner faith.
I can agree with that. The works are the visible part, and can be directly observed by a third party. The faith that inspires or motivates, that part is invisible, and therefore must be inferred. We can never directly know what's in another person's heart.
I believe that every human has a "god," so to speak. It doesn't necessarily have to be an invisible man in the sky. Look at the greedy businessman who cheats his customers and grinds his workers into poverty. He may go to church every week, but who does he actually serve: God or Mammon?
Everyone has a god, and they serve that god faithfully. It is impossible to hide your faith, it shines through in every act. Your entire conduct of life is inexorably determined by this "inner religion." It doesn't matter what faith you confess with your mouth; it doesn't even matter what you yourself consciously believe.
"As much virtue as there is, so much appears; as much goodness as there is, so much reverence it commands." I don't believe that there is much goodness in organized religion, because it doesn't appear. The reverence that it commands seems forced; it doesn't come from the heart; people are just going through the motions. They confess all the while, more loudly than ever before, that they believe these doctrines to be literally true, but their works show something else.
I like to call this bad faith. The sure sign of bad faith is when, unlike the Amish, you are no longer satisfied with the control of your own behavior, but now expect others to conform. To use a simple example: why the blue laws? If you think it is sinful to drink on Sunday, don't drink on Sunday. Why do you have to force others to abstain? Worry about your own salvation, and then let everyone else go to hell. When you try to force others, it shows you have a nagging doubt. The Amish show by their conduct that they have purified themselves of these corrupting doubts.
It reminds me of the Jews of old, as Paul describes them, who try to force others to be circumcised. What does that prove? Galatians 6: "Those who want to impress people by means of the flesh are trying to compel you to be circumcised. The only reason they do this is to avoid being persecuted for the cross of Christ. Not even those who are circumcised keep the law, yet they want you to be circumcised that they may boast about your circumcision in the flesh."
Every time a believer tries to make you conform to their program, you can rest assured that they merely want to "glory in your flesh," because their own faith is so weak.