Luther's Treatment of the 'Disputed Books'
of the New Testament
Lutheran theologians like to make a distinction between the books of the New Testament which were unanimously received as canonical in the early church (the so-called Homologoumena or undisputed books) and the books which were disputed by some (the Antilegomena). In this class of 'disputed books' are the Epistle to the Hebrews, James, Jude, 2 Peter, 2 and 3 John, and the Revelation of John. These books are considered to be canonical in modern Lutheran churches, with the caveat that they are not quite on the same level as the other books as complete expressions of evangelical truth, and should be used with care.
Luther himself took the liberty of criticizing some of these books in a polemical manner which few Lutherans today would find completely acceptable. He had a low view of Hebrews, James, Jude, and the Revelation, and so when he published his New Testament in 1522 he placed these books apart at the end. In his Preface to Hebrews, which comes first in the series, he says, "Up to this point we have had to do with the true and certain chief books of the New Testament. The four which follow have from ancient times had a different reputation."
Luther's criticism of these books will perhaps be found disgraceful and even shocking to modern Christians, but it should be pointed out that his attitude was not so shocking in the context of the late Middle Ages. Erasmus had also called into question these four books in the Annotationes to his 1516 Greek New Testament, and their canonicity was doubted by the Roman Catholic Cardinal Cajetan (Luther's opponent at Augsburg. See Reu, Luther's German Bible, pp. 175-176). The sad fact is, the Roman Catholic Church had never precisely drawn the boundaries of the biblical canon. It was not necessary to do so under the Roman system, in which the authority of the Scriptures was not much higher than that of tradition, popes, and councils. It was not until the Protestant Reformers began to insist upon the supreme authority of Scripture alone that a decision on the 'disputed books' became necessary.
If Luther's negative view of these books were based only upon the fact that their canonicity was disputed in early times, we would have expected him to include 2 Peter among them, because this epistle was doubted more than any other in ancient times. But it is evident from the prefaces that Luther affixed to these four books that his low view of them had more to do with his theological reservations against them than with any historical investigation of the canon.
From Biblical Researcher.com. (BTW, they reproduce Luther's introduction to each of the above writings farther down the page)
One must add that the scholar Luther was under the delusion that he had the most authetic texts at his disposal, that he was looking at the TRUE texts of Scripture which were far superior to the Vulgate. Fact is that Erasmus' Bible was based on some inferior Greek texts, as were the standard Engliush translations of the whole Bible including the KJB.