John Owen writes in the Introduction to Calvin’s Commentary on Romans:
“We have set before us in this Epistle especially two things, which it behoves us all rightly to understand — the righteousness of man and the righteousness of God — merit and grace, or salvation by works and salvation by faith. The light in which they are exhibited here is clearer and brighter than what we find in any other portion of Scripture, with the exception, perhaps, of the Epistle to the Galatians. Hence the great value which has in every age been attached to this Epistle by all really enlightened Christians; and hence also the strenuous efforts which have often been made to darken and wrest its meaning by men, though acute and learned, yet destitute of spiritual light. But let not the simple Christian conclude from the contrariety that is often found in the expositions on these two points, that there is no certainty in what is taught respecting them. There are no contrary views given of them by spiritually-minded men. Though on other subjects discussed here, such men have had their differences, yet on these they have ever been found unanimous: that salvation is from first to last by grace, and not by works, has ever been the conviction of really enlightened men in every age, however their opinion may have varied in other respects. It may seem very strange, when we consider the plain and decisive language, especially of this Epistle, and the clear and conclusive reasoning which it exhibits, that any attempt should ever be made by a reasonable being, acknowledging the authority of Scripture, to pervert what it plainly teaches, and to evade what it clearly proves. But a right view of what human nature is, when unrenewed, as exhibited in God’s Word, and as proved by history and made evident by observation, enables us fully to account for what would otherwise remain an enigma. No truth is more fully confirmed by facts (and it ought ever to be remembered) than that “the natural man receiveth not the things of the Spirit of God,” and that he “cannot know them, because they are spiritually discerned.” This declaration clearly accounts for the fact, that men of great learning have often misunderstood many things in Scripture, and such things as are plain enough even to the unlettered when spiritually enlightened. The learned Scribes and Rabbins were blind leaders of the blind, when even babes understood the mysteries of the kingdom of God: and no better then the Scribes are many learned men, professing Christianity, in our day.
There is indeed a special reason why, on these points, unenlightened men should contrive means to evade the obvious meaning of Scripture; for they are such things as come in constant contact with a principle, the strongest that belongs to human nature in its fallen state. Other doctrines may be held as speculations, and kept, as it were, at a distance; but when we come to merit and grace, to work and faith, man’s pride is touched; and as long as under he is its prevailing influence, he will be certain, in some way or another, direct or evasive, to support merit in opposition to grace, or works in opposition to faith. When the authority of tradition supplanted the authority of Scripture, the doctrine of merit so prevailed, that the preposterous idea, that merits were a salable and a transferable commodity, gained ground in the world. A notion of this kind is too gross and absurd to be entertained by any who acknowledge God’s Word as the only umpire in religion; and yet what is not essentially different has often been maintained; for to say that salvation is partly by faith and partly by works, is really the same thing, inasmuch as the principle of merit is thereby admitted. Man naturally cleaves to his own righteousness; all those who are ignorant are self-righteous, and all the learned who understand not the gospel; and it is wonderful what ingenious evasions and learned subtleties men will have recourse to in order to resist the plain testimony of Scripture. When they cannot maintain their ground as advocates of salvation alone by merits, they will attempt to maintain it as advocates of a system, which allows a part to grace and a part to works — an amalgamation which Paul expressly repudiates, Romans 11:6.
But it is remarkable how the innate disposition of man has displayed itself in this respect. Conscious, as it were, in some measure of moral imperfections, he has been striving for the most part to merit his salvation by ceremonial works. This has been the case in all ages with heathens: their scarifies, austerities, and mechanical devotions were their merits; they were the works by which they expected to obtain happiness. God favored the people of Israel with the rituals of religion, which were designed merely as aids and means to attain and preserve true religion; but they converted them to another purpose, and, like the heathens, regarded them as meritorious performances, and expected God’s acceptance for the very religious acts which they exercised: and in order to make up, as it were, a sufficient quantity of merit, they made additions to those services which God had appointed, as though to multiply acts of this kind was to render their salvation more certain. The very same evil crept early into the Christian Church, and still continues to exist. The accumulation of ceremonies is of itself a sufficient proof, that salvation by faith was in a great measure lost sight of: we want no other evidence; it is what has been ever done whenever the light of truth has become dim and obscure. We see the same evil in the present day. Outward privileges and outward acts of worship are in effect too often substituted for that grace which changes the heart, and for that living faith which unites us to the Savior, which works by love and overcomes the world. The very disposition to over-value external privileges and the mere performances of religious duties, is an unequivocal evidence, that salvation by faith is not understood, or very imperfectly understood, and not really embraced.
The only remedy, as means for this evil, is that which we find employed by Paul in this Epistle. He begins by showing what every man, Jew and Gentile, is by nature; he proves by the clearest evidence, that all have sinned and become guilty before God. And having done this, he discloses the way of salvation which God himself has planned and revealed; and he teaches us, that it is altogether by grace and through faith that we can be saved, and not by works. In order cordially to embrace this latter truth, it is necessary to know the first, that we are sinners under condemnation. It is impossible, according to the very constitution of man’s mind, that he should really and truly accede to the one, without a real and deep knowledge of the other. The whole need not a physician, but the sick. It is only he who is really convinced of sin and who feels its guilt and its burden intolerable, that ever will, or indeed ever can, really lay hold on that free salvation which God has provided. And when this free salvation is really known, all other things compared with it will be deemed as nothing; and then all outward privileges will be viewed only as means, and all outward acts of religion only as aids and helps; and then also all our works, however great and self-denying, will be regarded in no way meritorious, but imperfect and defective, and acceptable only through the merits of our High Priest at God’s right hand.”