James 5:15

15. But it must be observed, that he connects a promise with the prayer, lest it should be made without faith. For he who doubts, as one who does not rightly call on God, is unworthy to obtain anything, as we have seen in James 1:5. Whosoever then really seeks to be heard, must be fully persuaded that he does not pray in vain.

As James brings before us this special gift, to which the external rite was but an addition, we hence learn, that the oil could not have been rightly used without faith. But since it appears that the Papists have no certainty as to their anointing, as it is manifest that they have not the gift, it is evident that their anointing is spurious.

And if he have committed sins. This is not added only for the sake of amplifying, as though he had said, that God would give something more to the sick than health of body; but because diseases were very often inflicted on account of sins; and by speaking of their remission he intimates that the cause of the evil would be removed. And we indeed see that David, when afflicted with disease and seeking relief, was wholly engaged in seeking the pardon of his sins. Why did he do this, except that while he acknowledged the effect of his faults in his punishment, he deemed that there was no other remedy, but that the Lord should cease to impute to him his sins?

The prophets are full of this doctrine, that men are relieved from their evils when they are loosed from the guilt of their iniquities. Let us then know that it is the only fit remedy for our diseases and other calamities, when we carefully examine ourselves, being solicitous to be reconciled to God, and to obtain the pardon of our sins.