If we are to appreciate that which is central in the gospel, if the jubilee trumpet is to find its echo again in our hearts, our thinking must be revolutionized by the realism of the wrath of God, of the reality and gravity of our guilt, and of the divine condemnation.
That justification does not mean to make holy or upright should be apparent from common use. When we justify a person we do not make that person good or upright. When a judge justifies an accused person he does not make that person an upright person. He simply declares that in his judgement the person is not guilty of the accusation but is upright in terms of the law relevant to the case. In a word, justification is simply a declaration or pronouncement respecting the relation of the person to the law which he, the judge, is required to administer.
This is what is meant when we insist that justification is forensic. It has to do with a judgement given, declared, pronounced; it is judicial or juridical or forensic. The main point of such terms is to distinguish between the kind of action which justification involves and the kind of action involved in regeneration. Regeneration is an act of God in us; justification is a judgement of God with respect to us. The distinction is like that of the distinction between the act of a surgeon and the act of a judge. The surgeon, when he removes an inward cancer, does something in us. That is not what a judge does; he gives a verdict regarding our judicial status. If we are innocent he declares accordingly... Justification means to declare or pronounce to be righteous.
In God's justification of sinner's there is no deviation from the rule that what is declared to be is presupposed to be. God's judgement is according to truth here as elsewhere. The peculiarity of God's action consists in this that he causes to be the righteous state or relation which is declared to be. We must remember that justification is always forensic or judicial. Therefore what God does in this case is that he constitutes the new and righteous judicial relation as well as declares this new relation to be. He constitutes the ungodly righteous, and consequently can declare them to be righteous. In the justification of sinners there is a constitutive act as well as a declarative. Or, if we will, we may say that the declarative act of God in the justification of the ungodly is constitutive. In this consists its incomparable character.
It is clear that the justification which is unto eternal life Paul regards as consisting in our being constituted righteous, in our receiving righteousness as a free gift, and this righteousness is none other than the righteousness of the one man Jesus Christ; it is righteousness of his obedience. Hence grace reigns through righteousness unto eternal life through Jesus Christ our Lord (Rom. 5:21). This is the truth that has been expressed as the imputation to us of the righteousness of Christ. Justification is therefore a constitutive act whereby the righteousness of Christ is imputed to our account and we are accordingly accepted as righteous in God's sight.
Justification is both a declarative and constitutive act of God's free grace. It is constitutive in order that it may be truly declarative. God must constitute the new relationship as well as declare it to be. The constitutive act consists in the imputation to us of the obedience and righteousness of Christ. The obedience of Christ must therefore be regarded as the ground of justification; it is the righteousness which God not only takes into account but reckons to our account when he justifies the ungodly.