John Calvin's commentary was translated from the original Latin and edited by John Owen. Here is what John Owen had to say on page 313 of book 22 of Calvin's Commentaries:
The design of alluding to the faith of devils seems to have been this, to shew that though a man may believe and tremble, yet if he does not obey God and do good works, he has no true evidence of faith. Obedient faith is that which saves, and not merely that which makes us tremble. The connexion with the preceding verse seems to be as follows,—
In the former verse the boaster of mere faith is challenged to prove that his faith is right and therefore saving; the challenger would prove his by his works. Then, in this verse, a test is applied—the very first article of faith is mentioned; "Be it that you believe this, yet this faith will not save you: the devils have this faith, and instead of being saved they tremble.
We are not saved by faith "alone." As John Owen intelligently understood, "Obedient faith is that which saves." If we are saved by faith alone, then prove to me you have true faith without having works connected with it. This is an utter impossibility! In order to prove your faith is real and genuine, it must have works connected to it. This is precisely the argument James was making. True faith is always accompanied by faith in action (works), which demonstrates and perfects that faith. That is what James directs us to with both Abraham and Rahab. You can see it with every instance of faith found in the Bible! Faith and works side by side.
We are not speaking of arbitrary works here. Professing faith in the Gospel and then going out and feeding the hungry does not prove a thing. The works will be closely related to the faith in question. Observe: The woman with the issue of blood believed if she just touched Jesus' garment that she would be healed, so she reached out and did exactly that. Abraham believed the promise of God and so if he slew his only son, he believed God could raise him back up from the dead, and so he acted in accordance with that faith. The action must match the belief. If someone believes the Gospel, repentance is necessarily inseparable from it. There are no ifs, and, or buts about it. The faith you proclaim will bear actions that are equivalent to it.
John Calvin writes, "[James'] object was only to shew that good works are always connected with faith; and, therefore, since he declares Abraham was justified by works, he is speaking of the proof he gave of his justification.
...he who professes that he has faith, must prove the reality of his faith by his works. Doubtless James did not mean to teach us here the ground on which our hope of salvation ought to rest..." (p. 314).
John Calvin makes the same point I have been making in the last four blog entries I have written in regard to James 2:14-26. John Calvin intelligently understood "that good works are always connected with faith." Our hope of salvation rests in Christ Jesus alone. Nothing more. Nothing less. Jesus + nothing = everything.
John Calvin writes, "And this work was not as it were the finishing or last work, for many things afterwards followed by which Abraham proved the increase of his faith. Hence this was not the perfection of his faith, nor did it then for the first time put on its form. James then understood no other thing than that the integrity of his faith then appeared, because it brought forth that remarkable fruit of obedience" (p. 315). James purposefully referred to Abraham and Rahab, "two persons so different in their character, in order more clearly to shew, that no one, whatever may have been his or her condition, nation, or class in society, has ever been counted righteous without good works. ... Whosoever, then, seeks to be counted righteous, though he may even be among the lowest, must yet shew that he is such by good works" (p. 316). We do not obtain righteousness by the merits of works. "We, indeed, allow that good works are required for righteousness" (p. 317).
For the Christian who feels the proud and stubborn need to argue against me in his/her disillusionment regarding "by faith alone," he/she now has the words of John Calvin, John Owen, Matthew Poole, Matthew Henry, and Simon J. Kistemaker to contend with. These men have said the same thing I have been saying, and they have made my case for me. How many other giants in the faith from the past would you like me to dig up and quote?
Obedient faith is that faith which saves. Good works are always connected with true faith. If you have faith alone without anything connected to it in order to verify it, then your faith is dead and vain and you are dead in your trespasses and sins and will find yourself in hell when you die. It is that simple. True faith is never inward; it is always outward. Faith is never idle. True faith is always accompanied inseparably by faith in action (works). Faith proves itself to be true by its works. If you have a problem with that truth, I suggest you take it up with God. Be aware, though, that you will lose.