Luther had published his German translation of the New Testament in 1522, and he and his collaborators completed the translation of the Old Testament in 1534, when the whole Bible was published.
He continued to work on refining the translation until the end of his life.
Others had previously translated the Bible into German, but Luther tailored his translation to his own doctrine.

Two of the earlier translations were the Mentelin Bible (1456) and the Koberger Bible (1484).
There were as many as fourteen in High German, four in Low German, four in Dutch, and various other translations in other languages before the Bible of Luther.

When he was criticised for inserting the word "alone" after "faith" in Romans 3:28, he replied in part: "[T]he text itself and the meaning of St. Paul urgently require and demand it.
For in that very passage he is dealing with the main point of Christian doctrine, namely, that we are justified by faith in Christ without any works of the Law. ...
But when works are so completely cut away—and that must mean that faith alone justifies—whoever would speak plainly and clearly about this cutting away of works will have to say, 'Faith alone justifies us, and not works'."

Luther did not include First Epistle of John 5:7-8, the Johannine Comma in his translation, rejecting it as a forgery.
It was inserted into the text by other hands after Luther's death.

Luther's translation used the variant of German spoken at the Saxon chancellery, intelligible to both northern and southern Germans.
He intended his vigorous, direct language to make the Bible accessible to everyday Germans, "for we are removing impediments and difficulties so that other people may read it without hindrance."

Published at a time of rising demand for German-language publications, Luther's version quickly became a popular and influential Bible translation.
As such, it contributed a distinct flavor to German language and literature.
Furnished with notes and prefaces by Luther, and with woodcuts by Lucas Cranach that contained anti-papal imagery, it played a major role in the spread of Luther's doctrine throughout Germany.
The Luther Bible influenced other vernacular translations, such as the Tyndale Bible (from 1525 forward), a precursor of the King James Bible.
Luther had published his German translation of the New Testament in 1522, and he and his collaborators completed the translation of the Old Testament in 1534, when the whole Bible was published. He continued to work on refining the translation until the end of his life. Others had previously translated the Bible into German, but Luther tailored his translation to his own doctrine.
Two of the earlier translations were the Mentelin Bible (1456) and the Koberger Bible (1484). There were as many as fourteen in High German, four in Low German, four in Dutch, and various other translations in other languages before the Bible of Luther.
When he was criticised for inserting the word "alone" after "faith" in Romans 3:28, he replied in part: "[T]he text itself and the meaning of St. Paul urgently require and demand it. For in that very passage he is dealing with the main point of Christian doctrine, namely, that we are justified by faith in Christ without any works of the Law. ... But when works are so completely cut away—and that must mean that faith alone justifies—whoever would speak plainly and clearly about this cutting away of works will have to say, 'Faith alone justifies us, and not works'."
Luther did not include First Epistle of John 5:7-8, the Johannine Comma in his translation, rejecting it as a forgery. It was inserted into the text by other hands after Luther's death.
Luther's translation used the variant of German spoken at the Saxon chancellery, intelligible to both northern and southern Germans. He intended his vigorous, direct language to make the Bible accessible to everyday Germans, "for we are removing impediments and difficulties so that other people may read it without hindrance."
Published at a time of rising demand for German-language publications, Luther's version quickly became a popular and influential Bible translation. As such, it contributed a distinct flavor to German language and literature. Furnished with notes and prefaces by Luther, and with woodcuts by Lucas Cranach that contained anti-papal imagery, it played a major role in the spread of Luther's doctrine throughout Germany. The Luther Bible influenced other vernacular translations, such as the Tyndale Bible (from 1525 forward), a precursor of the King James Bible.
Martin Luther