One issue that comes up again and again is the issue of justification by faith alone. As most people know, this was an issue of great importance to Luther and is viewed as one of the dividing lines of the Reformation. Accordingly, many Roman Catholics have been quick to accuse Luther of adding the word "alone" to his translation of Romans.
Jodocus Adolph Birkhaeuser writes:
In Rom. iii. 20, and Rom. v. 15, Luther inserted the word "only", and in Rom. iii. 28, after the words "we account a man to be justified by faith," he added the word alone, "by faith alone."(History of the church, from its first establishment to our own times, 1898) Mr. Birkhaeuser provides a footnote to this claim. The footnote states:
When charged with having falsified verse Rom. iii. 28, by adding the word "alone," he replied, "Should your Pope give himself any useless annoyance about the word sola (alone), you may promptly reply: 'It is the will of Dr Martin Luther that it should be so.'"
But today, although we have seen that some Roman Catholic apologists like Mr. Martignoni are making similar claims (link), we also see a new trend that recognizes that this older view was wrong. Anthony N. S. Lane writes: "Ever since Luther inserted the word 'alone' into his translation of Romans 3:28 this [sola fide] has been a major point of controversy." Mr. Lane also provides a footnote, but it is somewhat different from Mr. Birkhaeuser's. Mr. Lane notes: "Though Hans Küng points out that some pre-Reformation translations of Galatians 2:16 contained the formula "faith alone". (citation omitted)
Mr. Swan has already pointed out (at the link above) that Joseph Fitzmyer has confirmed that Luther's translation here was not a radical departure or unwarranted insertion. Indeed, as Mr. Swan pointed out, Fitzmeyer references the fact that Bellarmine had identified at least eight men who had translated Romans 3:28 to include the word "alone" ranging from Origen to Thomas Aquinas.
But, of course, Fitzmeyer has been tagged as a "liberal" within Catholicism, and consequently he sometimes gets dismissed as not being sufficiently scholarly or not being truly unbiased. However, it should be noted that Fitzmeyer is not all on his own here.
A certain man of German extraction, presently living in Italy wrote: "And he adds "we hold that a man is justified by faith apart from works of the law" (ibid., v. 28). At this point Luther translated: "justified by faith alone". I shall return to this point at the end of the Catechesis. ... [at the end of the Catechesis] For this reason Luther's phrase: "faith alone" is true, if it is not opposed to faith in charity, in love." (General Audience, 19 November 2008)
By now you have perhaps guessed who this man is: he is Joseph Ratzinger who goes by the title Pope Benedict XVI and is recognized as the earthly head of the Roman Catholic church. This sounds somewhat different from what we recall of Leo X's words against Luther and of Trent's condemnation of justification by faith alone. These times are different, though. Today we find statements put forth from the Vatican, such as the following: "Justification takes place "by grace alone" (JD 15 and 16), by faith alone, the person is justified "apart from works" (Rom 3:28, cf. JD 25)." (source)
You'd almost think that the Vatican has conceded that Luther was not just right about his translation, but that he was right about his doctrine. That thought would be wrong. Through careful sophistry the Vatican today has done what the Vatican in Luther's day was unable to do: they have found a way to affirm Luther's words while meaning precisely the opposite thing.
"Grace Alone" is not, in the Vatican's new double-speak, inconsistent with human cooperation. "Faith Alone" is not, in the Vatican's new double-speak, inconsistent with justification by human cooperation (recall Trent: "CANON IX.-If any one saith, that by faith alone the impious is justified; in such wise as to mean, that nothing else is required to co-operate in order to the obtaining the grace of Justification, and that it is not in any way necessary, that he be prepared and disposed by the movement of his own will; let him be anathema." and "CANON XIV.-If any one saith, that man is truly absolved from his sins and justified, because that he assuredly believed himself absolved and justified; or, that no one is truly justified but he who believes himself justified; and that, by this faith alone, absolution and justification are effected; let him be anathema." and "CANON XXVII.-If any one saith, that there is no mortal sin but that of infidelity [unbelief]; or, that grace once received is not lost by any other sin, however grievous and enormous, save by that of infidelity [unbelief]; let him be anathema." and again "CANON XI.-If any one saith, that men are justified, either by the sole imputation of the justice of Christ, or by the sole remission of sins, to the exclusion of the grace and the charity which is poured forth in their hearts by the Holy Ghost, and is inherent in them; or even that the grace, whereby we are justified, is only the favour of God; let him be anathema.") To which we might add many more such quotations.
What is the bottom line? Rome has been forced to acknowledge that Luther's translation was correct. Instead of going after the translation itself, there has been attempt to redefine the phrases "sola fide" (faith alone) and "sola gratia" (grace alone) to include a concept that can be adopted by those who believe that they contribute something of their own to their justification by co-operation.
Who has apostolic tradition? The answer, as always, is whoever sides with Scripture.