Francis Turretin: Justification by faith alone is of the greatest importance

This [doctrine of justification by faith alone] must be handled with the greater care and accuracy as this saving doctrine is of the greatest importance in religion. It is called by Luther “the article of a standing or a falling church.” By other Christians, it is termed the characteristic and basis of Christianity—not without reason—the principal rampart of the Christian religion. This being adulterated or subverted, it is impossible to retain purity of doctrine in other places. Hence Satan in every way has endeavored to corrupt this doctrine in all ages, as has been done especially in the papacy.

-Francis Turretin, "Institutes of Elenctic Theology," 2:633. (Quoted by Morecraft in "Authentic Christianity," vol. 2, p. 954.)

William Cunningham: Arminians and Romanists both deny the biblical doctrine of substitution and satisfaction by Christ

“Papists unite with Arminians in denying the necessity of a perfect righteousness, as the ground or basis of God’s act in accepting men’s persons, and giving them a right and title to heaven … As the Scriptures indicate that a perfect righteousness is necessary, as the ground or basis of our acceptance and admission to a right to life, as well as a full satisfaction as the ground or basis of our forgiveness or exemption from punishment, so they set before us such a perfect righteousness as available for us, and actually benefiting us, in the obedience which Christ, as our surety, rendered to all the requirements of the law.” (William Cunningham, "Historical Theology," vol. II, pp. 49, 51; quoted in a compilation by Lee Irons)

Excerpts from Spurgeon's "A Defense of Calvinism"

I cannot, if I look ever so earnestly, discover any kind of reason in myself why I should be a partaker of Divine grace. If I am not at this moment without Christ, it is only because Christ Jesus would have His will with me, and that will was that I should be with Him where He is, and should share His glory.

... Then, in a moment, I saw that God was at the bottom of it all, and that He was the Author of my faith, and so the whole doctrine of grace opened up to me, and from that doctrine I have not departed to this day, and I desire to make this my constant confession, "I ascribe my change wholly to God."

... What circumstances were those in our power which led us to elect certain persons to be our parents? Had we anything to do with it? Did not God Himself appoint our parents, native place, and friends? Could He not have caused me to be born with the skin of the Hottentot, brought forth by a filthy mother who would nurse me in her "kraal," and teach me to bow down to Pagan gods, quite as easily as to have given me a pious mother, who would each morning and night bend her knee in prayer on my behalf? Or, might He not, if He had pleased, have given me some profligate to have been my parent, from whose lips I might have early heard fearful, filthy, and obscene language? Might He not have placed me where I should have had a drunken father, who would have immured me in a very dungeon of ignorance, and brought me up in the chains of crime? Was it not God's Providence that I had so happy a lot, that both my parents were His children, and endeavoured to train me up in the fear of the Lord?

John Newton used to tell a whimsical story, and laugh at it, too, of a good woman who said, in order to prove the doctrine of election, "Ah! sir, the Lord must have loved me before I was born, or else He would not have seen anything in me to love afterwards." I am sure it is true in my case; I believe the doctrine of election, because I am quite certain that, if God had not chosen me, I should never have chosen Him; and I am sure He chose me before I was born, or else He never would have chosen me afterwards; and He must have elected me for reasons unknown to me, for I never could find any reason in myself why He should have looked upon me with special love. So I am forced to accept that great Biblical doctrine. I recollect an Arminian brother telling me that he had read the Scriptures through a score or more times, and could never find the doctrine of election in them. He added that he was sure he would have done so if it had been there, for he read the Word on his knees. I said to him, "I think you read the Bible in a very uncomfortable posture, and if you had read it in your easy chair, you would have been more likely to understand it. Pray, by all means, and the more, the better, but it is a piece of superstition to think there is anything in the posture in which a man puts himself for reading: and as to reading through the Bible twenty times without having found anything about the doctrine of election, the wonder is that you found anything at all: you must have galloped through it at such a rate that you were not likely to have any intelligible idea of the meaning of the Scriptures."

... What did He foresee about my faith? Did He foresee that I should get that faith myself, and that I should believe on Him of myself? No; Christ could not foresee that, because no Christian man will ever say that faith came of itself without the gift and without the working of the Holy Spirit. I have met with a great many believers, and talked with them about this matter; but I never knew one who could put his hand on his heart, and say, "I believed in Jesus without the assistance of the Holy Spirit."

... If anyone should ask me what I mean by a Calvinist, I should reply, "He is one who says, Salvation is of the Lord." I cannot find in Scripture any other doctrine than this. It is the essence of the Bible. "He only is my rock and my salvation." Tell me anything contrary to this truth, and it will be a heresy; tell me a heresy, and I shall find its essence here, that it has departed from this great, this fundamental, this rock-truth, "God is my rock and my salvation." What is the heresy of Rome, but the addition of something to the perfect merits of Jesus Christ—the bringing in of the works of the flesh, to assist in our justification? And what is the heresy of Arminianism but the addition of something to the work of the Redeemer? Every heresy, if brought to the touchstone, will discover itself here. I have my own private opinion that there is no such thing as preaching Christ and Him crucified, unless we preach what nowadays is called Calvinism. It is a nickname to call it Calvinism; Calvinism is the gospel, and nothing else. I do not believe we can preach the gospel, if we do not preach justification by faith, without works; nor unless we preach the sovereignty of God in His dispensation of grace; nor unless we exalt the electing, unchangeable, eternal, immutable, conquering love of Jehovah; nor do I think we can preach the gospel, unless we base it upon the special and particular redemption of His elect and chosen people which Christ wrought out upon the cross; nor can I comprehend a gospel which lets saints fall away after they are called, and suffers the children of God to be burned in the fires of damnation after having once believed in Jesus. Such a gospel I abhor.

... All the purposes of man have been defeated, but not the purposes of God. The promises of man may be broken—many of them are made to be broken—but the promises of God shall all be fulfilled. He is a promise-maker, but He never was a promise-breaker; He is a promise-keeping God, and every one of His people shall prove it to be so. This is my grateful, personal confidence, "The Lord will perfect that which concerneth me"—unworthy me, lost and ruined me. He will yet save me ...

... I know there are some who think it necessary to their system of theology to limit the merit of the blood of Jesus: if my theological system needed such a limitation, I would cast it to the winds. I cannot, I dare not allow the thought to find a lodging in my mind, it seems so near akin to blasphemy. In Christ's finished work I see an ocean of merit; my plummet finds no bottom, my eye discovers no shore. There must be sufficient efficacy in the blood of Christ, if God had so willed it, to have saved not only all in this world, but all in ten thousand worlds, had they transgressed their Maker's law. Once admit infinity into the matter, and limit is out of the question. Having a Divine Person for an offering, it is not consistent to conceive of limited value; bound and measure are terms inapplicable to the Divine sacrifice. The intent of the Divine purpose fixes the application of the infinite offering, but does not change it into a finite work. Think of the numbers upon whom God has bestowed His grace already. Think of the countless hosts in Heaven: if thou wert introduced there to-day, thou wouldst find it as easy to tell the stars, or the sands of the sea, as to count the multitudes that are before the throne even now. They have come from the East, and from the West, from the North, and from the South, and they are sitting down with Abraham, and with Isaac, and with Jacob in the Kingdom of God; and beside those in Heaven, think of the saved ones on earth. Blessed be God, His elect on earth are to be counted by millions, I believe, and the days are coming, brighter days than these, when there shall be multitudes upon multitudes brought to know the Saviour, and to rejoice in Him. The Father's love is not for a few only, but for an exceeding great company. "A great multitude, which no man could number," will be found in Heaven. A man can reckon up to very high figures; set to work your Newtons, your mightiest calculators, and they can count great numbers, but God and God alone can tell the multitude of His redeemed. I believe there will be more in Heaven than in hell. If anyone asks me why I think so, I answer, because Christ, in everything, is to "have the pre-eminence," and I cannot conceive how He could have the pre-eminence if there are to be more in the dominions of Satan than in Paradise. Moreover, I have never read that there is to be in hell a great multitude, which no man could number.

There is much which I might admire in the theory of universal redemption, but I will just show what the supposition necessarily involves. If Christ on His cross intended to save every man, then He intended to save those who were lost before He died. If the doctrine be true, that He died for all men, then He died for some who were in hell before He came into this world, for doubtless there were even then myriads there who had been cast away because of their sins. Once again, if it was Christ's intention to save all men, how deplorably has He been disappointed, for we have His own testimony that there is a lake which burneth with fire and brimstone, and into that pit of woe have been cast some of the very persons who, according to the theory of universal redemption, were bought with His blood. That seems to me a conception a thousand times more repulsive than any of those consequences which are said to be associated with the Calvinistic and Christian doctrine of special and particular redemption. To think that my Saviour died for men who were or are in hell, seems a supposition too horrible for me to entertain. To imagine for a moment that He was the Substitute for all the sons of men, and that God, having first punished the Substitute, afterwards punished the sinners themselves, seems to conflict with all my ideas of Divine justice. That Christ should offer an atonement and satisfaction for the sins of all men, and that afterwards some of those very men should be punished for the sins for which Christ had already atoned, appears to me to be the most monstrous iniquity that could ever have been imputed to Saturn, to Janus, to the goddess of the Thugs, or to the most diabolical heathen deities. God forbid that we should ever think thus of Jehovah, the just and wise and good!

... The system of truth revealed in the Scriptures is not simply one straight line, but two; and no man will ever get a right view of the gospel until he knows how to look at the two lines at once. For instance, I read in one Book of the Bible, "The Spirit and the bride say, Come. And let him that heareth say, Come. And let him that is athirst come. And whosoever will, let him take the water of life freely." Yet I am taught, in another part of the same inspired Word, that "it is not of him that willeth, nor of him that runneth, but of God that sheweth mercy." I see, in one place, God in providence presiding over all, and yet I see, and I cannot help seeing, that man acts as he pleases, and that God has left his actions, in a great measure, to his own free-will. Now, if I were to declare that man was so free to act that there was no control of God over his actions, I should be driven very near to atheism; and if, on the other hand, I should declare that God so over-rules all things that man is not free enough to be responsible, I should be driven at once into Antinomianism or fatalism. That God predestines, and yet that man is responsible, are two facts that few can see clearly. They are believed to be inconsistent and contradictory to each other. If, then, I find taught in one part of the Bible that everything is fore-ordained, that is true; and if I find, in another Scripture, that man is responsible for all his actions, that is true; and it is only my folly that leads me to imagine that these two truths can ever contradict each other. I do not believe they can ever be welded into one upon any earthly anvil, but they certainly shall be one in eternity. They are two lines that are so nearly parallel, that the human mind which pursues them farthest will never discover that they converge, but they do converge, and they will meet somewhere in eternity, close to the throne of God, whence all truth doth spring.

... I ask the man who dares to say that Calvinism is a licentious religion, what he thinks of the character of Augustine, or Calvin, or Whitefield, who in successive ages were the great exponents of the system of grace; or what will he say of the Puritans, whose works are full of them? Had a man been an Arminian in those days, he would have been accounted the vilest heretic breathing, but now we are looked upon as the heretics, and they as the orthodox. We have gone back to the old school; we can trace our descent from the apostles. It is that vein of free-grace, running through the sermonizing of Baptists, which has saved us as a denomination. Were it not for that, we should not stand where we are today. We can run a golden line up to Jesus Christ Himself, through a holy succession of mighty fathers, who all held these glorious truths; and we can ask concerning them, "Where will you find holier and better men in the world?" No doctrine is so calculated to preserve a man from sin as the doctrine of the grace of God. Those who have called it "a licentious doctrine" did not know anything at all about it. Poor ignorant things, they little knew that their own vile stuff was the most licentious doctrine under Heaven. If they knew the grace of God in truth, they would soon see that there was no preservative from lying like a knowledge that we are elect of God from the foundation of the world. There is nothing like a belief in my eternal perseverance, and the immutability of my Father's affection, which can keep me near to Him from a motive of simple gratitude. Nothing makes a man so virtuous as belief of the truth. A lying doctrine will soon beget a lying practice. A man cannot have an erroneous belief without by-and-by having an erroneous life. I believe the one thing naturally begets the other. Of all men, those have the most disinterested piety, the sublimest reverence, the most ardent devotion, who believe that they are saved by grace, without works, through faith, and that not of themselves, it is the gift of God. Christians should take heed, and see that it always is so, lest by any means Christ should be crucified afresh, and put to an open shame.

(Spurgeon, "A Defense of Calvinism")

Biblical words for "imputation" and "justification" refer to God's objective work, not subjective, internal, progressive moral reformation within man

"The true import of the word 'justify' seems to have been corrupted among the Romanists, when the Latin Vulgate alone was taken as the guide; for the Latin word, from which our English term is derived, taken aside from its use seems to carry with it the signification, not of declaring, but making a man just; but in the original terms, both in the Hebrew and Greek, there is no ambiguity. The words express uniformly the sense which we have put on them; that is, they mean, to account, to esteem, to declare a person to be just or righteous, and never to make a man just or righteous by the infusion of grace. Justification and Sanctification should, therefore, be carefully distinguished, although they should never be separated. The difference between these two benefits which arise from union with Christ, is well expressed in the answer to the 77th Question, in our Larger Catechism. 'Although sanctification be inseparably joined with justification, yet they differ, in that, God in justification imputeth the righteousness of Christ, in sanctification his Spirit infuses grace, and enableth the exercise thereof: in the former, sin is pardoned, in the other, it is subdued: the one doth equally free all believers from the avenging wrath of God, and that perfectly in this life, that they never fall into condemnation: the other is neither equal in all, nor in this life perfect in any, but growing up to perfection." (Archibald Alexander, “A Treatise on Justification by Faith Alone”)


"To inquire what is meant by the imputation of this righteousness; which is the way in which it becomes ours and indeed is the only way in which it can become ours. The Hebrew word כשח in Genesis 15:6 and the Greek word logizwmai used by the apostle here, signifies to estimate, reckon, impute, or place something to the account of another. So the righteousness of Christ is estimated, reckoned, and imputed to be his people's, and is placed to their account as such by God the Father, and looked upon as much by him as their justifying righteousness or as though it had been wrought by them, in their own persons. That this righteousness becomes ours this way, is manifest. For in the same way that Adam's sin became ours, the same way the righteousness of Christ becomes ours; or the same way we are made sinners by the disobedience of Adam, are we made righteous by the obedience of Christ (Rom. 5:19). For as by one man's disobedience, many were made sinners. So by the obedience of one, shall many be made righteous. Now Adam's sin became ours, or we were made sinners, through his sin; by imputation, it was reckoned, it was placed to the account of all his posterity. So Christ's righteousness becomes ours, or we are made righteous, through that righteousness of his; by the imputation of it to us, it is reckoned, it is placed to our account. Again, the same way our sins became Christ's, Christ's righteousness becomes ours, as appears from 1 Corinthians 5:21. He who knew no sin, was made sin for us, that we might be made the righteousness of God in him. Now the way in which Christ was made sin for us, was by imputation; he never had any sin inherent in him, though he had it transferred unto him and laid upon him. So the way in which we are made the righteousness of God, must be by the imputation of Christ's righteousness, and indeed we cannot be made righteous any other way, than by imputation. For the objects of justification are ungodly persons in themselves; for God justifies the ungodly, as in the verse preceding my text. Now if they are ungodly in themselves, then they are not justified by a righteousness of their own, it must be by the righteousness of another. And if they are justified by the righteousness of another, that other's righteousness must be some way or other made theirs, it must be placed to their account, and reckoned as their own, which is only done by an imputation of it to them." (John Gill, "The DOCTRINE OF IMPUTED RIGHTEOUSNESS Without Works Asserted And Proved")


“I may also remind you that Augustine, and a few of the other fathers, misled by this etymology, and their ignorance of Greek, conceived and spoke of justification as a change of moral state, as well as of legal condition. Here is the poisonous germ of the erroneous doctrine of the Scholastics and of Trent concerning it; a striking illustration of the high necessity of Hebrew and Greek literature, in the teachers of the Church.” (R.L. Dabney, “Systematic Theology”)

John Owen: Licentiousness was charged against Paul's doctrine of justification, but Paul showed it was the grounds of our sanctification

“I know that the doctrine here pleaded for [namely, justification by faith through the imputation of the righteousness of Christ] is charged by many with an unfriendly aspect towards the necessity of personal holiness, good works, and all gospel obedience in general, yea, utterly to take it away. So it was at the first clear revelation of it by the apostle Paul, as he frequently declares. But it is sufficiently evinced by him to be the chief principle of, and motive unto, all that obedience which is accepted with God through Jesus Christ, as we shall manifest afterwards. However, it is acknowledged that the objective grace of the gospel, in the doctrine of it, is liable to abuse, where there is nothing of the subjective grace of it in the hearts of men; and the ways of its influence into the life of God are uncouth unto the seasonings of carnal minds. So was it charged by the Papists, at the first Reformation, and continues yet so to be. Yet, as it gave the first occasion unto the Reformation itself, so was it that whereby the souls of men, being set at liberty from their bondage unto innumerable superstitious fears and observances, utterly inconsistent with true gospel obedience, and directed into the ways of peace with God through Jesus Christ, were made fruitful in real holiness, and to abound in all those blessed effects of the life of God which were never found among their adversaries.” –John Owen, The doctrine of Justification by Faith, through the Imputation of the Righteousness of Christ; explained, confirmed, and vindicated

John Robbins: The blasphemous charge of antinomianism against Paul's doctrine of justification demonstrates he taught justification apart from works

John Robbins explains the separation -- in history and in modern times -- between those who teach salvation by faith alone and those who heretically and damnably add works:

The Bible clearly and emphatically teaches that a sinner is saved by belief of the Gospel alone, "apart from the deeds of the law." That is why the blasphemous charge of antinomianism arose against the Gospel in the first place. If Paul and the other apostles had taught a false gospel of faith plus obedience as the way of salvation, the charge of antinomianism would never have been brought against them. Neither Rome nor many so-called "Reformed" theologians seem to understand that salvation is not a result of good works; good works are a result of salvation. It was that difference that divided the Christians from the Romanists in the sixteenth century, and it is that difference that divides the Christians from the Romanists in the twenty-first century. (John Robbins, R.C. Sproul on Saving Faith)

Francis Turretin: Justification is of the greatest importance

Francis Turretin explains the importance, biblically and historically, of justification by faith:

The topic concerning Vocation and Faith begets the Topic concerning Justification, which must be handled with the greater care and accuracy as this saving doctrine is of the greatest importance in religion. It is called by Luther, the article of a standing and falling church; by other Christians it is termed the characteristic and basis of Christianity not without reason, the principle rampart of the Christian religion, and, it being adulterated or subverted, it is impossible to retain purity of doctrine in other places. Whence Satan in every way has endeavored to corrupt this doctrine in all ages; as has been done especially in the Papacy: for which reason it is deservedly placed among the primary causes of our Secession from the Roman Church and of the Reformation. (Francis Turretin, Forensic Justification)

R.L. Dabney: Justification is central to all doctrines of theology

R.L. Dabney explains the central importance of justification within history (Reformation vs. Romanism) and within Christian theology (the person and work of Christ, the nature of the Triune God, how man is right with God, and so forth):

It is obvious to the first glance, that it is a question of the first importance to sinners, ‘How shall man be just with God?’ The doctrine of justification was the radical principle, as we have seen, out of which grew the Reformation from Popery. It was by adopting this that the Reformers were led out of darkness into light. Indeed, when we consider how many of the fundamental points of theology are connected with justification, we can hardly assign it too important a place. Our view of this doctrine must determine, or be determined by our view of Christ’s satisfaction; and this, again, carries along with it the whole doctrine concerning the natures and person of Christ. And if the proper deity of Him be denied, that of the Holy Spirit will very certainly fall along with it; so that the very doctrine of the Trinity is destroyed by extreme views concerning justification. Again, "It is God that justifieth." How evident, then, that our views of justification will involve those of God’s law and moral attributes? The doctrine of original sin is also brought in question, when we assert the impossibility of man’s so keeping the law of God, as to justify himself. It is a more familiar remark, that the introduction of the true doctrine of justification excludes that whole brood of Papal inventions, purgatory and penance, works of supererogation, indulgences, sacrifice of the mass, and merit of congruity acquired by alms and mortifications. (R.L. Dabney, Systematic Theology, ch. 23: Justification)

John Gerstner: The church always taught "Sola Fide" implicitly, and the Reformers explicitly defended the doctrine against apostate Romanists

John Gerstner explains the history of "Sola Fide" within the church:

One may say generally of the history of the doctrine of justification that solafideanism (justification-by-faith-alone-ism) was taught implicitly, but not explicitly, from the beginning of the church. That is, it was known in the early church that salvation was by faith alone, but not until the sixteenth century was the church called upon to define that teaching more precisely. Those in the church who had quietly apostasized opposed this essential truth (adherents of Tridentine Roman Catholicism), while the faithful (Protestants), affirmed it. The Reformers defined and refined the doctrine in the fires of controversy. (Dr. John Gerstner, History of the Doctrine of Justification)

Joel R. Beeke: Christ's righteousness, alien to the believer, is the formal cause of justification, and faith is the instrumental cause

Joel R. Beeke explains that faith is the instrumental cause of justification and that Christ's righteousness -- alien to the believer and imputed to him -- is the formal or meritorious cause, the ground upon which we are justified:

Protestant theology, on the other hand [set against Romanism], maintained that faith is the instrumental cause of justification, while the alien righteousness of Christ, external to the believer and imputed to him, is the formal cause, i.e., the ground upon which God can justly justify sinners. ‘For he hath made him to be sin for us, who knew no sin; that we might be made the righteousness of God in him’ (2 Corinthians 5:21; cf. Romans 3:26). It is critical to maintain that this formal cause of justification resides in Christ’s righteousness alone, for all the Scriptures dealing with the fundamentally depraved nature of man make clear that there is no righteousness inherent in the natural man upon which a divine verdict of justification could be based. ‘They are all gone aside, they are together become filthy; there is none that doeth good, no, not one’ (Psalm 14:3). For the Reformers, faith was the conscious, personal immediate reliance of a sinner on Christ alone. (Dr. Joel R. Beeke, Justification by Faith Alone, Soli Deo Gloria (1995), p. 90)

R.C. Sproul: Forensic justification is the article by which the sinner stands or falls before God's supreme tribunal

R.C. Sproul explains the forensic nature of justification as the doctrine by which the sinner stands or falls before God:

At the heart of the controversy between Roman Catholic and Reformation theology is the nature of justification itself. It is a debate not merely about how or when or by what means a person is justified, but about the very meaning of justification itself.

Reformed theology insists that the biblical doctrine of justification is forensic in nature. What does this mean? In the popular jargon of religion, the word forensic is used infrequently. The word is not foreign, however, to ordinary language. It appears daily in the news media, particularly with reference to criminal investigations and trials. We hear of "forensic evidence" and "forensic medicine" as we listen to the reports of criminologists, coroners, and pathologists. Here the term forensic refers to the judicial system and judicial proceedings.

The term forensic is also used to describe events connected with public speaking. Schools hold forensic contests or events that feature formal debates or the delivery of speeches.

The link between these ordinary usages of forensic and its theological use is that justification has to do with a legal or judicial matter involving some type of declaration. We can reduce its meaning to the concept of legal declaration.

The doctrine of justification involves a legal matter of the highest order. Indeed it is the legal issue on which the sinner stands or falls: his status before the supreme tribunal of God. (R.C. Sproul, Imputed Righteousness: The Evangelical Doctrine)

James Buchanan: Four major points of controversy regarding justification

There are four major points regarding justification, according to James Buchanan (Justification, p. 113-114): 1) “The nature of Justification …”; 2) “the ground of Justification …”; 3) “the means of Justification …”; 4) “the effect of Justification …” “Under one or other of these topics every question of any real importance on the subject of Justification may be conveniently ranked; and they were all involved in the great controversy between the Reformers and the Church of Rome.”

• Nature: “…the fundamental error of the Church of Rome consisted in confounding [justification] with sanctification. … Justification, considered as an act of God, is the mere infusion, in the first instance, and the mere recognition, in the second, of a righteousness inherent in the sinner himself; and not an act of God’s grace, acquitting him of guilt, delivering him from condemnation, and receiving him into His favour and friendship” (pp. 114-115)
• Ground: “…the fundamental error of the Church of Rome consisted in substituting the inherent righteousness of the regenerate, for the imputed righteousness of the Redeemer. … The merits of Christ were rather, according to their doctrine, the procuring cause of that regenerating grace by which we are made righteous; while the inherent personal righteousness which is thus produced, is the real proximate ground of our justification. … But that His righteousness imputed is the sole and all-sufficient ground of our justification, which neither requires nor admits of any addition being made to it in the shape either of suffering or obedience, and which is effectual, for that end, without the aid of any other righteousness, infused and inherent,--the strenuously denied.” (pp. 116-117).
• Means: “… the fundamental error of the Church of Rome consisted in denying that we are justified by that faith which ‘receives and rests on Christ alone for salvation, as He is freely offered to us in the Gospel.’ They affirmed that we are justified, not simply by faith in Christ, for faith might exist where there is no justification, but by faith informed with charity, or love, which is the germ of new obedience;--that this faith is first infused by baptism, so as to delete all past sin,--original sin, in the case of infants, and both original and actual sin in the case of adults, duly prepared to receive it,--while it is restored or renewed, in the event of post-baptismal sin, by confession and absolution, which effectually deliver the sinner from all punishment, except such as is endured in penance, or in purgatory. … Accordingly faith, to which so much efficacy and importance are everywhere ascribed in Scripture, was, first of all, defined as a mere intellectual belief, or assent to revealed truth, such as an unrenewed mind might acquire in the exercise of its natural faculties, without the aid of divine grace, and described as having, in itself, no necessary connection with salvation, but as being only one of seven antecedent dispositions or qualifications, which always precede, in the case of adults, but are not invariably followed by, Justification” (p. 118-119).
• Effect: “… the fundamental error of the Church of Rome consisted in holding, that it was neither so complete in its own nature, nor so infallibly secured, as to exempt him from the necessity of making some further satisfaction for sin, or to warrant the certain hope of eternal life” (p. 122).
  

William Cunningham: The Reformers agreed on faith alone, but faith is not meritorious

William Cunningham explains the loose sense in which we are justified by faith alone, not by any inherent righteousness within us:

The Reformers were unanimous and decided in maintaining the doctrine that faith alone justified; that men were justified by faith only; and this gave rise to a great deal of discussion between them and the Romanists … By this position that faith alone justifies, the Reformers meant in general that faith was the only thing in a man himself, to the exclusion of all personal righteousness, habitual or actual, of all other Christian graces, and of all good works, to which his forgiveness and acceptance with God are attributed or ascribed in Scripture … They did not teach that this faith which alone justified was ever alone, or unaccompanied with other graces; but, on the contrary, they maintain that, to adopt the words of our Confession, ‘it is ever accompanied with all other saving graces, and is no dead faith, but worketh by love’ [Larger Catechism, q. 153]. … Again, the Reformers did not ascribe to faith, in the matter of justification, any meritorious or inherent efficacy in producing the result, but regarded it simply as the instrument or hand by which a man apprehended or laid hold of, and appropriated to himself, the righteousness of Christ; and it was only in that very general and, strictly speaking, loose and improper sense, which was consistent with this view of its function and operation in the matter, that they called it, as Calvin does … the cause of justification. (William Cunningham, Historical Theology [vol. 2], p. 23; published by Still Waters Revival Books)

John Gill: Justification by the righteousness of Christ is the "essence of the Gospel"

John Gill on the importance of the doctrine of justification:

The doctrine of justification by the righteousness of Christ is a doctrine of great importance; the apostle speaks of it as if the essence of the gospel lay in it; and calls the opposite to it, justification by the works of the law, another gospel; (see Gal. 1:6,7; 3:8), it is a fundamental article of the gospel; some have called it, the "basis" of Christianity; it was the great doctrine of the reformation; what our first reformers made their chief study; and by it cut the sinews of "popery", the antichristian doctrines of penance and purgatory, of pardons and indulgences, of the merit of good works, works of supererogation, &c. Luther used to call it, "articulus stantis vel cedentis ecclesiae" the article of the church, by which it stands or falls; as this is, the church is; if this obtains, the church is in a well settled and prosperous state; but if this loses ground, and is rejected, it is in a ruinous one: if this is a rule to judge by, it may be easily discerned, in what case the church, and interest of religion, now are. This doctrine is the ground and foundation of all solid joy, peace, and comfort, in this life, and hope of eternal glory hereafter. (John Gill, A Body of Doctrinal Divinity: Book 6—Chapter 8: Of Justification)