Packer and Beeke: Faith is not the ground of justification, but rather the instrument of receiving and resting in the person and work of Christ alone

“When Paul paraphrases this verse [Gen. 15:6] as teaching that Abraham’s faith was reckoned for righteousness (Rom. 4:5, 9, 22), all he intends us to understand is that faith—decisive, whole-hearted reliance on God’s gracious promise (vss. 18ff)—was the occasion and means of righteousness being imputed to him. There is no suggestion here that faith is the ground of justification.”
-J.I. Packer (quoted by Dr. Joel R. Beeke in “Justification by Faith Alone,” pp. 56-57)

“… Habakkuk 2:4 … quoted in Romans 1:17, Galatians 3:11, and Hebrews 10:38, is ultimately fulfilled in the righteousness that comes by faith in the gospel of Christ, for which the law itself teaches us to look (Romans 3:21-22; 10:4). Paul’s explanation of Habakkuk has inspired not only Martin Luther but countless other believers to place their faith in a righteousness not their own, but that of Jesus Christ who is called ‘THE LORD OUR RIGHTEOUSNESS’ (Jeremiah 23:6).”
-Dr. Joel R. Beeke, “The Relation of Faith to Justification” (in the book, “Justification by Faith Alone,” pp. 57-58)

J. Gresham Machen: A high view of the Law is neccesary for a proper understanding of the Gospel

A new and more powerful proclamation of law is perhaps the most pressing need of the hour; men would have little difficulty with the gospel if they had only learned the lesson of the law.

As it is, they are turning aside from the Christian pathway; they are turning to the village of Morality, and to the house of Mr. Legality, who is reported to be very skillful in relieving men of their burdens…

‘Making Christ Master’ in the life, putting into practice ‘the principles of Christ’ by one’s own efforts-these are merely new ways of earning salvation by one’s obedience to God’s commands…

So it always is; a low view of law always brings legalism in religion; a high view of law makes a man a seeker after grace. Pray God that the high view may again prevail. (J. Gresham Machen, What is Faith?, pp. 141-142)

James Buchanan: XXXIV Propositions Concerning Justification

James Buchanan's Propositions regarding the biblical doctrine of justification (Justification, Banner of Truth, 1997 -- reprinted from the 1867 original) :

• I – “Justification is a legal, or forensic, term, and is used in Scripture to denote the acceptance of any one as righteous in the sight of God” (p. 226).
• II – “While ‘Justification’ is a forensic or judicial term, it is used in Scripture to denote, sometimes the acceptance of a sinner as righteous in the sight of God,--sometimes the manifestation or proof of his acceptance, by which it is attested and made sure: and this variety in the application of it is the ground of an important theological distinction,--the distinction between ACTUAL and DECLARATIVE Justification” (p. 233).
• III – “The distinction between actual and declarative Justification,--viewed in connection with the difference between a living and a dead faith,--affords a sufficient explanation of the apparent discrepancy between the teaching of Paul and James” (p. 239).
• IV – “The term ‘Justification’ denotes, either an act of God, or a privilege of His people; and, in both cases, that which is denoted by it includes absolution and acceptance,--the full pardon of sin, admission into God’s favour, and a title to eternal life” (p. 250).
• V – “Justification, although inseparably connected with, is yet essentially different from, Sanctification; and the former is not founded on the latter, as its procuring or meritorious cause” (p. 264).
• VI – “As Justification is a forensic, legal, or judicial term, so that which is denoted by it must necessarily have some relation to the Law and Justice of God” (pp. 268-269).
• VII – “The rule of Justification, as revealed to man in his state of original righteousness, was the Law of God in the form of a divine covenant of life” (p. 270).
• VIII – “The breach of the Law in its covenant form by the sin of our first parents, rendered it for ever impossible that either they, or any of their descendants, should be justified on the ground of their personal righteousness” (p. 277).
• IX – “The law of God, which is the rule of man’s duty, is also a revelation of God’s eternal Justice and Holiness” (p. 288).
• X – “The doctrine of the Law is presupposed in that of the Gospel, and the justifying righteousness which is required in the one, is revealed in the other” (p. 291).
• XI – “It was God’s eternal purpose to overrule the fall of man for His own glory, by a signal manifestation of all His moral perfections, in justifying ‘the ungodly,’ through Christ as Mediator” (p. 293).
• XII – “Christ, as Mediator, was ‘made under law’ as the substitute, representative, and surety, of His people” (p. 298).
• XIII – “The Mediatorial work of Christ on earth properly consisted in His humiliation, sufferings, and obedience; or, as it is stated by the Apostle, ‘He humbled Himself, and became obedient unto death, even the death of the Cross’ [Phil. 2:8]” (pp. 301-302).
• XIV – “The Mediatorial work of Christ, including both His sufferings and His obedience, constituted a complete and effectual satisfaction to the Law and justice of God” (pp. 307-308).
• XV – “The Justification of sinners is directly connected in Scripture with the Mediatorial work of Christ, as a satisfaction rendered to the Law and Justice of God” (p. 310).
• XVI – “The righteousness, which is the ground of a sinner’s Justification, is denoted or described by various terms in Scripture, so that its nature may be determined by simply comparing these terms with one another; and then ascertaining whether there be any righteousness to which they are all equally applicable, and in which they all coincide, in the fullness of their combined meaning” (p. 315).
• XVII – “This righteousness,--being the merit of a work, and not a mere quality of character,--may become ours by being imputed to us, but cannot be communicated by being infused; and must ever continue to belong primarily and, in one important respect, exclusively to Him by whom alone that work was accomplished” (p. 320).
• XVIII – “The imputation of Christ’s righteousness to His people, as the immediate ground of their pardon and acceptance with God, may be proved, deductively, from the character in which He acted, as their representative; and from the vicarious nature of the work which He undertook to accomplish” (p. 328).
• XIX – “The righteousness of Christ, considered as the merit of His Mediatorial work, is, not partially, but entirely imputed; and is effectual for the complete Justification of all who believe in His name” (p. 332).
• XX – “The imputation of sin and righteousness is not, in any bad sense of the expression, a ‘legal fiction,’ as it has been offensively called; nor is it a theory, invented by man, but a fact, revealed by God” (p. 334).
• XXI – “When God forgives sinners, and accepts them as righteous in His sight, they are ‘justified freely by His grace, through the redemption which is in Christ Jesus’” (p. 339).
• XXII – “Justification ‘by grace’ is identified, in Scripture, with Justification ‘by faith,’ and opposed to Justification ‘by works’” (p. 343).
• XXIII – “Justification by the ‘works of the law’ is expressly excluded in the case of every sinner; while Justification by a righteousness not his own, is as expressly revealed” (p. 345).
• XXIV – “Justification by ‘works,’ such as are really ‘good’ and ‘acceptable to God,’ is also excluded in the case of believers, excepting only as it may be manifested or declared by them” (p. 353).
• XXV – “We are justified by Faith, and Faith is counted, or imputed to us, for righteousness; but Faith is not itself the righteousness on account of which we are justified” (p. 366).
• XXVI – “The Faith, by which we are justified, is a spiritual grace,--as being the gift of God, and one of the fruits of His Spirit,--and, as such, is acceptable and well-pleasing to Him ‘through Jesus Christ’” (p. 373).
• XXVII - “A real influence or efficacy is ascribed to Faith in connection with our Justification, but it is such only as belongs to a divinely appointed means of receiving and appropriating a free gift” (p. 379).
• XXVIII – “The only warrant of Faith is the Word of God, and that Word is sufficient, not only to entitle every sinner to receive and rest upon Christ for his personal salvation, but to make it his duty to do so without delay” (p. 380).
• XXIX – “We are justified by faith only, simply because it is by faith, and by no other grace, that we believe the truth concerning Christ, and rely on Him alone for salvation as He is freely offered to us in the Gospel” (p. 385).
• XXXI – “The Father, the Son, and the Holy Spirit are revealed as concurring together in the whole purpose and plan of man’s redemption; but as sustaining each of them, a distinct office, and undertaking a different part of the work, in carrying that purpose and plan into effect” (pp. 388-389).
• XXXII – “The work of the Holy Spirit is as necessary for our Justification as the work of Christ Himself; but it is not necessary for the same reasons, nor is it effectual for the same ends” (p. 392).
• XXXIII – “The work of the Spirit consists in ‘bearing witness to Christ,’ and applying to men the redemption which He obtained for them, so as to make it effectual for their complete and everlasting salvation” (p. 397).
• XXXIV – “Regeneration and Justification are simultaneous; and no man is justified who is not renewed, nor is any man renewed who is not also, and immediately, justified” (p. 400).
  

James Buchanan: Biblical justification answers the most pressing questions regarding sinful man's standing before a just God

James Buchanan on the importance of the biblical doctrine of justification:

[The biblical doctrine of justification] is an attempt to solve the deepest problem, and to answer the most anxious question, which conscience continually prompts men to raise, but which their minds strive in vain to determine--'How shall a man be just with God?' or, 'How can God be just,' and yet 'justify the ungodly?' That great problem may seldom occur to those that are habitually unmindful of God, and of their relation to Him; and should it be suggested to their minds, it will probably be lightly dismissed, as long as they cherish slight views of sin, and have little or no sense of their solemn responsibilities and prospects as subjects of the righteous government of God. ... The Gospel of Christ alone has presented that problem in all its magnitude, and in its just proportions; and the Gospel of Christ alone has offered a solution of it, based on a full view of the Attributes of God,--of the unalterable requirements of His Law,--of the principles and ends of His Moral Government,--and of the state, character, and prospects of man, as a dying yet immortal being, chargeable with past guilt, and still depraved by inherent sin. (James Buchanan, Justification, pp. 405-406, Banner of Truth, 1997 -- reprinted from the 1867 original)

. . .

The mere statement of such a problem, and of its indispensable conditions,--including the glory of God, the honour of His law, and the ends of His moral government, as well as the pardon of sin, and the salvation of sinners,--is peculiar to the Gospel of Christ, and may well be regarded as a proof of its superhuman origin: but the solution of it, by the Incarnation, Substitution, and Satisfaction of the Son of God Himself, is such a marvellous manifestation of divine wisdom as 'it could never have entered into the mind of man to conceive.' For none other than the infinite mind of God was capable of such a conception, either of Love, or of Justice, as that on which it is based; and far less of carrying it into effect in the stupendous work of Redemption. It may be esteemed as 'foolishness' by those who have never seriously considered, or sufficiently realised, the conditions of the great problem; but no sooner is any one brought, under the teaching of the Word and Spirit of God, to apprehend them aright, and to apply them in earnest to the case of his own soul, than that which hitherto seemed to be 'foolishness,' is seen to be the 'wisdom of God.' Hence,--while the very repugnance with which it is regarded by many affords ample evidence that it could never have been invented by men,--the best and most convincing evidence of its divine origin is discerned, when it is seen to be worthy of the infinite perfections of God, as well as adapted to the most urgent wants of man; and when 'He who commanded the light to shine out of darkness, shines into our hearts, to give us the light of the knowledge of the glory of God in the face of Jesus Christ.' (Ibid., pp. 407-408).

C.H. Spurgeon: The Gospel is unclear without the imputation of Christ's righteousness

C.H. Spurgeon on the imputation of Christ's righteousness:

When we say that the righteousness of Christ is imputed to an believing souls, we do not hold forth an exceptional theory, but we expound a grand truth, which is so consistent with the theory of the fall and the plan of pardon, that it must be maintained in order to make the gospel clear. I think it was this doctrine which Martin Luther called the article of standing or falling of the Church. I find a passage in his works which seems to me to refer to this doctrine rather than to justification by faith. He ought certainly to have said, "Justification by faith is the doctrine of standing or falling of the Church." But in Luther's mind, imputed righteousness we, so interwoven with justification by faith, that he could not see any distinction between the two. And I must confess, in trying to observe a difference, I do not see much. I must give up justification by faith if I give up imputed righteousness. True justification by faith is the surface soil, but then imputed righteousness is the granite rock which lies underneath it; and if you dig down through the great truth of a sinners being justified by faith in Christ, you must, as I believe, inevitably come to the doctrine of the imputed righteousness of Christ as the basis and foundation on which that simple doctrine rests. (C.H. Spurgeon, The Lord Our Righteousness)

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)