What Is The Doctrine Of Justification?

James Buchanan (1804-1870) explains:

BY Justification we mean—man’s acceptance with God, or his being regarded and treated as righteous in His sight—as the object of His favour, and not of His wrath; of His blessing, and not of His curse...

‘JUSTIFICATION IS AN ACT OF GOD’S FREE GRACE,—WHEREIN HE PARDONETH ALL OUR SINS,—AND ACCEPTETH US AS RIGHTEOUS IN HIS SIGHT,—ONLY FOR THE RIGHTEOUSNESS OF CHRIST,—IMPUTED TO US,—AND RECEIVED BY FAITH ALONE...’ 

PROP. 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.

It denotes an act of God; for ‘it is God which justifieth:’ ‘He is near that justifieth me;’—and it denotes a privilege of His people; for ‘being justified by faith, we have peace with God through our Lord Jesus Christ, by whom also we have access by faith into this grace wherein we stand, and rejoice in hope of the glory of God.’ In each of these aspects, some important truths have been revealed concerning it.

Considered as an act of God, who ‘justifies the ungodly,’ it is not a subjective operation producing a moral change in our personal character, although it is invariably accompanied by renewing and sanctifying grace; but an act which is external to us, and which effects an immediate and permanent change in our relation to God,—just such as is consequent on the sentence of a judge, by which any one is absolved from a charge of guilt,—or the act of adoption, by which any one is invested with the privileges of legal sonship. It is an act, too, which is completed at once, and not a work which is gradually accomplished by successive acts; for although we read of the continuance, as well as the commencement, of Justification, considered as the privilege of believers, and of the renewed exercise of forgiving mercy as often as they contract fresh sin, yet there is no second Justification, properly so called, but a decisive and unalterable change in our relation to God, which commences with our union to Christ, and is continued by our remaining in Him; an abiding state of Justification, which is the effect of that indissoluble union. ‘There is now no condemnation to them that are in Christ Jesus.’ ‘He that believeth … hath everlasting life, and shall never come into condemnation; but is passed from death unto life.’2 The act of Justification introduces believers into a state of Justification, which is stable and enduring, and which is described as ‘this grace wherein we stand,’ and as ‘a new life:’ for Christ is ‘our life.’ Justification, considered in the same aspect, is, still further, an act of God in time,—not His eternal purpose merely, as some Antinomians have held,—nor is it a mere revealing of what was always true, and is now only made known and believed; it is a real efficacious act of grace, by which God constitutes the sinner legally righteous, and accepts him as such, although till that hour he was not righteous, but guilty and condemned. It is an act of God with reference to individuals, and it takes place at a definite period in the life of each,—for as long as any one remains without Christ, and in a state of unbelief, he is charged with guilt, and exposed to wrath; but as soon as he believes and is united to Christ, his state in this respect is entirely changed. All who are justified were once ‘dead in trespasses and sins;’ and they continued in that state, till the decisive moment when, by an act of divine grace, they were taken out of it, and placed in a state of pardon and peace. ‘For as many as are of the works of the law, are under the curse: for it is written, Cursed is every one that continueth not in all things which are written in the book of the law to do them.’2 ‘He that believeth on Christ is not condemned; but he that believeth not is condemned already, because he hath not believed in the name of the only-begotten Son of God.’ ‘He that believeth on the Son hath everlasting life: and he that believeth not the Son shall not see life; but the wrath of God abideth on him.’ This act of God takes instant effect, and produces an immediate and complete change in the sinner’s whole relation to Him; it bestows the full and free pardon of sin, and translates him at once from a state of condemnation into a state of favour and peace. His person is first justified, and then his services are accepted: and should he afterwards incur fresh guilt, he is not suffered to fall again into condemnation, but, as an adopted child, he ‘is chastened of the Lord, that he should not be condemned with the world.’ ‘For whom the Lord loveth He chasteneth, and scourgeth every son whom He receiveth.’*

*Buchanan, J. (1867). The doctrine of justification: An outline of its history in the church and of its exposition from Scripture. (17,411, 250-252). Edinburgh: T&T Clark.