The necessity and inerrancy were well-established ideas, garnering little criticism, though they later came under debate from outside during the Enlightenment. The most contentious idea at the time though was the notion that anyone could simply pick up the Bible and learn enough to gain salvation. Though the reformers were concerned with ecclesiology (the doctrine of how the church as a body works), they had a different understanding of the process in which truths in scripture were applied to life of believers, compared to the Catholics' idea that certain people within the church, or ideas that were old enough, had a special status in giving understanding of the text.
What is the term for how the church as a whole works?
ecclesiology