There is a large standard Protestant reference work, . It first appeared in four very large volumes, with alphabetical articles on everything pertaining to the Bible. In 1976 there appeared a Supplement volume, which contained some new articles, and some older articles revised. This latest volume does have a new article on faith, on p. 333. Precisely the same as what we explained above.
Faith is a complex of belief, confidence, obedience, love.
By his own standard, the article on which his church would rise or fall has fallen. For in the first centuries there were in circulation many books that were called Gospels, with the names of Apostles on them. He thought that if a book preaches justification by faith strongly, it is inspired - otherwise not. But Luther never proved that that was the test. The Professor reviewed every way he could think of to determine which books are part of the Bible.