John Calvin on James 2:17

17 Is dead, being alone. He says that faith is dead, being by itself, that is, when destitute of good works. We hence conclude that it is indeed no faith, for when dead, it does not properly retain the name. The Sophists plead this expression and say, that some sort of faith is found by itself; but this frivolous caviling is easily refuted; for it is sufficiently evident that the Apostle reasons from what is impossible, as Paul calls an angel anathema, if he attempted to subvert the gospel. (Galatians 1:8.)

James 2:18-19

18 Yea, a man may say, Thou hast faith, and I have works: shew me thy faith without thy works, and I will shew thee my faith by my works.

18 Quin dicat quispam, Tu fidem habes, et ego opera habeo; ostende mihi fidem tuam sine operibus (alias, ex operibus) tuis, et ego tibi ex operibus meis ostendam fidem meam.

19 Thou believest that there is one God; thou doest well: the devils also believe, and tremble.

19 Tu credis quod Deus unus est, bene facis; et daemones credunt, ac contremiscunt.