I am at work so I cannot offer a lengthy response, but a great deal of the length of Daniel’s response is in showing how even thoughtful Catholics have struggled to reconcile what superficially appear to be contradictory expressions, Paul version James, when we know for a fact the Holy Spirit inspired the writings of both. When I first was converted and read through the Bible for the first time, I encountered a number of passages that seemed to be contradictions, this among them, and it took some thought and lengthy analysis to find a solution. But there always was one.
I dont think the solution being offered here is too burdensome to the prima facie sense of either writer. Paul is speaking in strict forensic, legal terms, I.e., how does our legal status before God go from “condemned” to “forgiven,” to which the answer must ever be faith, not works, lest we fall into the heresy of Pelagianism.
Whereas James, whose entire tone was pragmatic and NOT forensic, describes what accompanies saving faith, and neither Luther nor any knowledgeable Protestant would deny that saving faith does not come to the party alone, but brings its most intimate companion, righteousness that flows from a heart of love for God and neighbor. Thus Paul describes the legal effect, and James the pragmatic effect, of faith suffcient to save lost sinners.
So this is not hard, or obscure. It is a mature reading of the text, which by its nature insists on a reconciliation, but once it is found, is clear and simple enough for a child to understand.
There is no contradiction even in appearance. Nowhere does St. Paul say that we are justified by faith alone. Both inspired authors are thoroughly Catholic. If Luther felt that there was a contradiction, instead of inventing a new religion he should have listened to how the Fathers of the Church defined the roles of faith and good works in justification by grace alone.