But be doers of the word, and not hearers only, deceiving yourselves. For if any one is a hearer of the word and not a doer, he is like a man who observes his natural face in a mirror; for he observes himself and goes away and at once forgets what he was like. But he who looks into the perfect law, the law of liberty, and perseveres, being no hearer that forgets but a doer that acts, he shall be blessed in his doing. James 1:22–25 (RSV)
Luther did not have a high opinion of the Epistle of James. It is understandable as James does emphasize doing as a believer, not merely being a hearer of the Word.
Luther and James are both correct. Luther would argue that it is by grace alone we are saved, apart from any works. James argues that faith if it does nothing with its redemption, is dead.
Ascension Day is this coming Thursday. It was on Ascension Day that Jesus gave the Great Commission to His disciples. The Commission is full of activity and doing. The faith within the disciples is to be shown in how they act.
Our Lord was clear about this long before Ascension Day. He taught His disciples that following Him meant taking up our cross daily and following Him. Our Lord does not nullify salvation grace but teaches that our salvation compels us to act for the blessing of the world.
Thus, we can be clear, with Luther, we affirm that we are saved by grace alone through faith alone. We can add nothing to our salvation in Christ. St. James is equally clear that our salvation is meaningless if we hoard it selfishly for ourselves. A redeemed person will act on their faith.
So, giving thanks for so great a mercy which save a fallen wretch like me, I can also now say, "How might I serve Thee this day?"