To be clear, I'm not critiquing the rich theology of the Reformation. What I'm talking about is how Protestant theology became watered down at a popular level.
Specifically, the Reformation focus on sola fide--faith alone--has tended to reduce faith to mere belief, mental assent to a proposition. We are "saved" through "belief."
As we know, the Bible cautions us about this reduction. We all can quote James 2:
What good is it, my brothers and sisters, if someone claims to have faith but does not have works? Surely that faith cannot save, can it?
Because of passages like this, we know how Martin Luther infamously described James as an "epistle of straw."
A lot of this tension, though, is due to thin understandings of the Greek word pistis. Pistis doesn't simply mean "belief." Pistis means fidelity, trust, fealty, reliability, loyalty, faithfulness, and allegiance. This proper, richer understanding of pistis bridges the gap between justification and sanctification.
Understanding pistis as fidelity, loyalty, and allegiance is exactly the point being made by James 2. How can you say you are loyal when you engage in betrayal? How can you say you have trust when you break faith? How can you pledge allegiance while fighting for the other side? Such a "faith" cannot save you because it's not faith in the first place. As James points out, the demons know Jesus is Lord, they have mental assent, but they are not loyal to Jesus, and it's this loyalty that is salvific. Such a conception of faith, in contrast to the thin "belief alone" conception that predominates within evangelical culture, is bettered positioned to support spiritual formation and discipleship efforts.
Perhaps the Reformation should have went with fidelitas sola--loyalty alone. If it had, a whole lot of this "faith versus works" drama would have been cleared up.
