There is also the passage in James 2:17: "So faith by itself, if it has no works, is dead." He did well to say this, for he was reprimanding those who thought that faith is merely a historical opinion about Christ. For just as Paul calls one type of faith "true," and the other "feigned," so James calls the one kind "living" and the other "dead." A living faith is that efficacious, burning trust in the mercy of God which never fails to bring forth good fruits. That is what James says in ch. 2:22: "Faith was completed by works." Likewise, because his works declared that Abraham had this living faith, Scripture was fulfilled where it says (v. 23): "Abraham believed God, and it was reckoned to him as righteousness." Therefore, the whole point that James is making is that dead faith, that frigid "opinion" of the Parisian theologians, does not justify, but a living faith justifies. But a living faith is that which pours itself out in works. For he speaks as follows (v. 18): "Show me your faith apart from works, and I by my works will show you my faith." But he does not say: "I shall show you works without faith." My exposition squares most harmoniously with what we read in James: "So faith by itself, if it has no works, is dead." Therefore, it is obvious that he is teaching here merely that faith is dead in those who do not bring forth the fruit of faith, even though from external appearances they may seem to believe.
- Philip Melanchthon (1497-1560), Loci Communes Theologici