One of the claims that anti-UOJ partisans make is that Lutheran tradition prior to the 19th century did not hold to UOJ. They attribute it to a Pietist theologian named Georg Christian Knapp. See Greg Jackson's argument here:
They claim that C.F.W. Walther, Adolf Hoenecke, and mid-west Lutheranism got this idea from Knapp.
Of course, there are a couple of problems with this, including the difficulties (as my wife the historian will tell you) with showing direct historical influence. Just because two people have the same idea does not mean influence has taken place.
Notice, in the section that deals with the supposed connections between Knapp and other thinkers, he simply shows dates and the availability of Knapp's work. He never gives a Walther citation saying "hey, this Knapp guy is great." Neither does he show that Walther possessed a copy of his work or that there is some kind connection to Calvinism- other than that he was translated in English by a Calvinist. The translation issue is meaningless since most mid-western Lutheran still spoke German well in the 19th century. Some even into the 20th. My mother was born in 1951 and spoke German at home. She had to learn English when she went to public school at age 6! All he actually does imply that there is some sort of connection. This is not much of an argument for influence.
The second problem (beyond that of demonstrating influence) is that one can cite Luther and the Confessions, stating that all are forgiven by the death of Christ.
Steve Goodrich has helpfully posted some Luther quotes endorsing UOJ. I also have my own (lifted them from the second chapter of my dissertation).
"It is expressly stated here that Christ came and removed the sin of the world so completely that it is entirely deleted, entirely forgiven. But to refuse the Helper, to refuse to hear the Man who abolishes sin, and, more than this, to want to kill Him and to persevere in sin—that is vile and base. It is terrible to hear this proclamation, which brings remission of sin and release from death, maligned as heresy and to see this Helper persecuted. We preach this every day, and that is what goes on. I did not suck these words out of my finger; no, you hear that this is spoken by Christ Himself. Nevertheless, it is decried as heresy. Should our God not become angry? Should He not dispatch pestilence, famine, pope, Turk, Tartars, Sacramentarians, Anabaptists, and all sorts of sectaries to plague us? Our refusal to accept the Son surely deserves such punishment. It is terrible to proclaim that one should not accept and love a Helper and Savior who remits sin. Whoever acts this way and becomes ungrateful to God has a right to expect God to punish him with Turks, Tartars, and Anabaptists, and that schismatic spirits, sectaries, and false brethren will rain and snow down on him." (Luther's Works 22:384)
UPDATE. Another citation from Steve:
As though Christ wished to say: “Whoever believes, does not go to hell; whoever does not believe, already has the sentence of death pronounced on him.” Why? Well, because he does not believe in Christ. This is the judgment: that such an ineffably comforting doctrine of God’s grace, procured for the world through Christ, is proclaimed, but that the world still wants to believe the devil rather than God and His beloved Son. And this despite the fact that God assures us: “Sin, hell, judgment, and God’s wrath have all been terminated by the Son.”
Now what is still lacking? Why the judgment if all sin has been removed by the Son? The answer is that the judgment is incurred by man’s refusal to accept Christ, the Son of God. Of course, man’s sin, both that inherited from Adam and that committed by man himself, is deserving of death. But this judgment results from man’s unwillingness to hear, to tolerate, and to accept the Savior, who removed sin, bore it on His shoulders, and locked up the portals of hell. (Luther's Works 22:382-383)
From the Large Catechism:
""God has given us the Gospel, in which he offers free forgiveness before we prayed for it or even thought of it." (Large Catechism,Lord's Prayer, Fifth Petition, 88. Triglot, p. 273)
From the Galatians Commentary of 1535. Luther states Christ is the “greatest person” (maxima persona), “the greatest sinner” (maximus peccator) and the only sinner (solus peccator). Luther writes:
“But because in the same Person, who is the highest, the greatest, and the only sinner, there is also eternal and invincible righteousness, therefore two converge: the highest, greatest and only sin; and the highest, the greatest, and the only righteousness.” (LW 26:281)
Bear in mind that the Formula of Concord endorses the Galatians Commentary of 1535, which my citations are from. So, UOJ is directly confessionally endorsed.
Also note that Luther clearly states that no one in the whole world has a sinful status before God because Christ is the "greatest" sinner and "only" sin.
So much for the Knapp thesis.
A Brief Note.
One thing that this debate has show me is that UOJ is a very necessary way of talking. I was a little bit more tolerant about it before I entered the debate and said "hey, if you don't want to say the word atonement constitutes=justification, be my guest." But now I'm of a different mind. I came the conclusion that if you don't say that atonement constitutes forgiveness, then what are you really saying about atonement? I mean, what is atonement if it isn't forgiveness?If as sin is paid for, how can it still exist?
When all those people had "atonement" made for them in the Levitical cult, it was forgiveness that was coming about. The Jubilee, which Isaiah and Jesus in Luke tell us is the type of his redemptive work, objectively forgave everyone's debts. Again, to be consistent with the Bible, I'm very committed now to saying we've got to use the language of universal forgiveness.
If indeed "God has laid on him the sins of us all" (Isa. 53) then how can our sins still be on us? Where are they? On him!
Secondly, I think that if say that justification only occur because of faith, then you'll make the gospel into law. In other words, if justification and forgiveness are not prior to faith and cause faith by it's proclamation ("you sins are forgiven for the sake of Jesus") then faith is a condition for justification. Faith wouldn't be a means of receiving justification, rather it will cause it.
Pastorally, telling someone that they are justified because of their faith is a disaster. It draws back into ourselves. I begin to worry about whether or not my faith is authentic, and not whether or not the objective work of Christ is real and pro nobis.
The irony is that this all leads back to Pietism and it's self-obsession over whether or not faith was real. It's ironical because that's the thing that my opponents have accused me of here. If it's dependent on my faith, rather than my faith receiving it, then I will navel gaze and wonder if I've done a good enough job having faith
All this makes me conclude that using the language of UOJ is absolutely necessary for the Lutheran Church. I still also think that my opponents are not really heretics in a conceptual sense, but are using language that very, very seriously endangers the Christian faith.