Forensic justification is defined as strictly legal declaration as justified, rather than reckoning or acknowledging someone as righteous to justify him. In other words, a person is declared righteous despite being a sinner, and remain an ungodly sinner, but God overlooks justice for him and let him go. Is it acceptable if we characterize this as a false justification or forged justification - contrary to fact? As if a forged document of righteousness is given by God? And what is the origin of this theological jargon called forensic justification, who came up with it? The false justification characterization fits well with Luther's own description.
Luther’s “Sermon on Our Blessed Hope”:
We see grain sowed in the ground. Reason now asks: What happens to the grain in winter that has been sowed in the ground? Is it not a dead, moldy, decayed thing, covered with frost and snow? But in its own time it grows from that dead, moldy, decayed grain into a beautiful green stalk, which flourishes like a forest and produces a full, fat ear on which there are 20, 30, 40 kernels, and thereby finds life where only death existed earlier. Thus God has done with heaven, earth, sun and moon, and does every year with the grain in the field. He calls to that which is nothing that it should become something and does this contrary to all reason. Can He not also do something which serves to glorify the children of God, even though it is contrary to all reason?
In another quote:
Conceived in sorrow and corruption, the child sins in his mother’s womb. As he grows older, the innate element of corruption develops. Man has said to sin: ‘Thou art my father’—and every act he performs is an offense against God; and to the worms: ‘You are my brothers’—and he crawls like them in mire and corruption. He is a bad tree and cannot produce good fruit; a dunghill, and can only exhale foul odors. He is so thoroughly corrupted that it is absolutely impossible for him to produce good actions. Sin is his nature; he cannot help committing it. Man may do his best to be good, still his every action is unavoidably bad; he commits a sin as often as he draws his breath. (Werke, (Wittenberg Edition), Vol. III, p. 518.)
It is surprising that such a traditional fundamental Lutheran theology is not known by most common reformed believers, including Evangelicals; so I'd encourage the Lutherans not to rush in closing the question, but allow everyone to learn despite the disagreements. Neither Luther nor his followers are embarrassed in admitting their theology, and if one rejects them, they should be honestly realize that they reject the traditional reformed theology, rather than being defensive and attempting to censor the studies and debates on these topics. Had it been for N. T. Wright, we wouldn't have known about this, because the Lutheran scholars have responded to Wright's NPP interpretations of Rom 4:5, by defending the traditional view, and only then the laymen like us discovered these beliefs through them.
First, as many commentators note, God is here said to do what he forbids judges to do. In a striking parallel to Rom 4:5 the Greek text of Isa 5:23 pronounces a woe on οἱ δικαιοῦντες τὸν ἀσεβῆ (“those who justify the ungodly). In Prov 17:15 “he who justifies the wicked and he who condemns the righteous are both alike an abomination to the LORD.” In Exod 23:7 the Lord himself swears that he will not justify the ungodly.
Daniel Wallace writes addressing to Wright's controversy.
Among his many points, Sprinkle notes that in the OT God did not justify wicked people, citing, inter alia, Exod 23.7 and Isa 5.23. In my class on the exegesis of Romans, which I have taught at Dallas Seminary for the past seven years, I have argued that these two texts are key to Paul’s thinking and that the Jews of his day would have realized this. Exodus 23.7 clearly involves legal language. It is this language which lies behind Paul’s points in Rom 3.23–24 and 4.4–5. In v. 7 we see δικαιόω used with ἀσεβής: ‘you shall not justify the ungodly for a bribe’ (οὐ δικαιώσεις τὸν ἀσεβῆ ἕνεκεν δώρων). This can only mean ‘you shall not declare innocent the ungodly for a bribe.’ Three things are significant here: (1) δικαιόω means, in this legal context, ‘declare righteous/innocent’; it does not mean ‘make righteous.’ (2) The person who might be declared innocent is in fact guilty (ἀσεβῆ), precisely the situation we have in Rom 3:23–24. (3) The word for bribe is δῶρον, a cognate of δωρεάν found in Rom 3:24. It would of course not do for Paul to say that God declares sinners righteous ‘for a bribe,’ so an appropriate substitute is needed—one that is a cognate of δῶρον, but does not use ἕνεκεν or imply anything except that God acts freely when he justifies sinners. δωρεάν is the accusative singular of δωρεά; as such, it is adverbial (always so in the NT) and means ‘freely.’ It is not insignificant that we again see in the LXX of Isa 5.23 the collocation of δικαιόω with ἀσεβής and δῶρον. And again, we see that δικαιόω must almost surely mean ‘declare innocent’ since the pronouncement is made on the ungodly who do not deserve it.
Dr. Craig quotes Henri Blocher and D. G. Dunn,
“That God’s righteousness towards the peoples he has created includes wrath and judgment as well as faithfulness and salvation is clearly implicit in the sequences Romans 1:16-18 and 3:3-6.” Those who deny that dikaiōsynē is a forensic term, Dunn says, pay insufficient attention to Romans 4:4-5, “where the forensic background is clear in the allusion to the legal impropriety of a judge ‘justifying the ungodly’. . . , and where again the thought is entirely of attributing a righteous status to one who is unrighteous.” Dunn’s point is that Paul’s referring to God as “him who justifies the ungodly” (Romans 4:5) recalls the Old Testament description of the unjust judge who justifies the wicked (Proverbs 17:15), which is an abomination in the Lord’s sight. French theologian Henri Blocher remarks on “the staggering audacity of Paul’s combination of words: God who justifies the ungodly (Rom 4:5)
The Cambridge Dictionary defines "impropriety" as: behavior that is dishonest, socially unacceptable, or unsuitable for a particular situation: financial/legal impropriety allegations of sexual impropriety.