What was Martin Luther's opinion of Book of James and Hebrews?

Answer 1

In general, he didn't seem to care too much for most of what Peter, James, and John wrote. He referred to James as the "epistle of straw", and didn't care too much for Hebrews. It seems that his main reason for wanting to delete James was that it is the only place in scripture where "faith" and "alone" appear in the same verse, and James dares to teach the opposite of what Luther was trying to teach: namely, that we are saved by "faith alone" (sola fide). Though he purported to also teach the new idea of "sola scriptura", his abuse of the scriptures of his day, along with some of his other writings and teachings, show that he tended to believe far more in his own ideas than all that he found in Holy Scripture.

Answer 2

he did not like it too much