Most Protestants seem to accept the Lutheran argument that Justification by Faith Alone is the article by which the church stands or falls. It is the core of the gospel and as long as 'a church' adheres to it, or doesn't formally deny it…it is still legitimate.
So for many the Roman Catholic Church was the legitimate Body of Christ up until one day in 1563 when the Council of Trent formally anathematized Sola Fide. At the moment there was a thunderclap or something and the church of Roman ceased to be the church. Conveniently there were now Lutheran, Anglican, and Reformed bodies which could take up the mantle.
Pardon my cynicism here but this is rotten history, hence my ironic tone. Anyone who has bothered to study the history of Roman Catholicism will see that on a practical level Justification by Faith Alone was never taught…certainly not after the 5th century…if ever at all. Just because they didn't openly deny it??? This is a bizarre way of looking at things. By teaching Sacerdotalism…that is practically speaking...denying Sola Fide. What more is there to say?
The problem is those who are committed to continuous church 'Institution' have a meltdown if you suggest there was no 'Institution' from roughly 500-1500. The church was in a state of apostasy. I would argue the church was scattered here and there…in North Africa, East Anglia, the Cottian Alps, Southern Bohemia, the Rhineland, the Languedoc….at different times and in different places. The Church is not an Institution in that sense……it is the body of Christ adhering to THE TRUTH.
Justification by Faith Alone was the issue that drove Luther to stand against the might of the Holy Roman Empire…but what's the real issue here? The issue no one seems to talk about is authority. If the doctrine of the church is allowed to integrate scripture and tradition interpreted by an Inspired Magisterium, then even if 'The Church' teaches something differently than the plain teaching of Scripture…well that's okay…that's how God led them.
But if not…if Scripture is understood to be the Word of God and sufficient (even though Luther didn't really work this out)……then at that point someone can stand alone if need be and defy the Institution. It was because Luther saw the Scriptures had a higher authority than the church…whether he expressed it that way or no….that's the real issue. Sola Fide was but a facet of a great jewel that Luther discovered. Actually he didn't really seem to grasp what he had found. He was more than a little bit of a disaster.
So, I would assert the issue of Authority is what defines the church. When the church abandons that, it has on a theoretical level abandoned the gospel. How long that takes to 'work out'….well that's something else entirely and frankly depends on a lot of different circumstances.
Constantinian Historians struggle with what to do with groups like the Waldensians or Hussites. Even though they were obviously of a Protestant flavour they were outside the Institution, the Edifice. So what many have done is framed the argument thus…
Well, the Waldensians, Petrobrussians, Lollards, Hussites, Unitas Fratrum and the rest were all very interesting groups, little lights in the midst of the dark ages, but in reality they weren't Protestants because you don't see a clear expression of Justification by Faith Alone. So, really Rome was the real church and the real cultural mover and shaker and so that's where our focus needs to be.
That's not a straw man argument. I've encountered this time and time again. I would say it is a classic case of a presupposition (Constantinianism is right) leading to a wrong assumption (the concern is Institutional Continuity) causing the wrong questions to be asked (regarding Justification). If they admit Rome was a false church in the middle ages and the true church was not an institution but people meeting in barns, basements, caves, and forests…..their whole view of church and culture is thrown into turmoil.
So is Protestantism defined by Sola Fide? I don't think so. Maybe for the Lutherans….in some ways they never moved beyond that. They claim Sola Scriptura but in practice deny it. If Sola Scriptura is the real issue….suddenly the medieval dissenters look pretty good. All of them were more or less arguing that point.
IF, I contend they were following Scripture, if they were regenerate, reading God's Word, learning His ways, His paths…they would understand Grace. Was it elaborated in their writings? We don't have a lot of writings. Now we do with Wycliffe…and you don't find Sola Fide there. But you do find Divine Election. I'm sorry but someone who is grasping that truth is not teaching a works based gospel.
One final note, a can of worms. The medieval church influenced by Aristotle and the other ancients developed Scholasticism……a method of developing and discerning theology. The dissenters didn't seem to be shall we say, as keen on this method. I know, I know for the most part they were simple unsophisticated folk….but everyone said they knew their Bibles. Do we believe in the Perspicuity of Scripture or not? Does one have to be a Thomas Aquinas or Bernard of Clairvaux to know God? Evidently not. I don't expect to see either of those two in paradise.
Bottom line, I contend Scholasticism was a wrong way to do theology. Calvin and some of the other first and second generation Reformers were influenced by Humanistic (Renaissance Humanism, not modern) thought and it led them to deal with the texts in a dynamic flexible way. They were not systematizing. Even Calvin's Institutes exhibit a different spirit from the later 17th century men like Turretin. And when we reach the 19th century and find the Hodges, Warfield, Dabney and the rest….something has been lost. The method has changed. A grid like thinking…an Aristotelian method has replaced the more Redemptive-Historical hermeneutic of Calvin. I'm no huge fan of Calvin. I used to worship him but I still appreciate his Institutes and Commentaries a hundredfold versus the non-Biblical methods of the later Reformed.
Armstrong makes this case in Calvinism and the Amyraut Heresy. It is another book attacked by those fervently devoted to static Institutional view of history. If Hodge was right and Calvin wrong…then fine, but you can't pretend they were coming at the Bible in exactly the same way. Many similar conclusions but a different method, a different spirit. I remember years before I had even heard of Armstrong's book discussing these very issues with close friends. We had immersed ourselves in Calvin and could see a difference. Another book which was extremely eye opening was Iain Murray's Spurgeon vs. Hyper-Calvinism. Our pendulums had swung to the hyper-side after leaving Arminianism. It's only rational…systematic to do so. Iain Murray's book The Forgotten Spurgeon helped with that…and then he helped bring balance with the Hyper-Calvinism book. It enabled us to see there was more to the theology than a two-dimensional grid.
This is a huge issue….but back to the Proto-protestants.
I will be called a heretic, but Sola Fide often becomes Hyper Sola-fideism. The medieval heretics took books like James seriously, but they also often accepted what the Word said about the Sovereignty of God and Election. They could not reconcile this dynamic…Aristotelian Systematics cannot either. So Systematics redefines and explains it away…..the medievalists stuck with the Word. I would argue Calvin did so more than the later Reformed. Again understand that I'm not a Calvin hero-worshipper. He deserves many critiques, but on this point compared to what came later………..sterling.
What is the church? Is the gospel reducible to something as simple as Sola Fide? What is the Kingdom?