However, the same technology that made this possible also undermined it. Since it was so (relatively) easy to print a thousand copies of a vernacular New Testament, unauthorized translations were being created and disseminated, many with (no doubt) honest errors, and many with politically and religiously motivated differences from each other. This complicated the reassuring directive to rely on scripture alone; whose scripture should you rely on? How can you tell whose translation you're reading? If you can't, or aren't equipped to, compare different translations, how do you know if you're relying on words that were translated correctly? “For the public, however, it was difficult to distin- guish between authenticity and falsehood in printed Bibles, since all that they had in their hands was sola Scriptura, the text alone.”
Luther's New Testament is an interesting example of this. His name did not appear on any editions of his translation before the eighth. By then, his translation was such a big deal that it was being pirated by many printers and booksellers--and even other competing theologians went to great lengths to make their translations look like Luther's, so that people would buy theirs without knowing. Although he had a device created, "Luther's Rose," so that people would know it was an authorized copy of his translation they were buying, non-authorized translations were still printed and sold at a rate of 4 to 1.
Luther himself began to be frustrated with other's critiques of his work, as well. In one verse from Romans, he added the word "allein" (only) which was not in the original Greek and Latin versions from which he was translating. His excuse was that, like Paul speaking in koine Greek, he wanted to bring the Bible to people in common German, and given German grammar, this instance demanded the use of the word "allein"--otherwise (to paraphrase) it would sound funky to people and distance them from the text. He modeled himself after the apostle Paul, "a spiritual reproduction of the saint" that came about because of the literal printed reproductions of the New Testament.