Luther had completed his catechisms in 1529, before the Diet of Augsburg.  While visiting the churches in Saxony, he became convinced that pastors and teachers needed materials to help them understand and teach God’s Word.  Sermons that he preached in 1528 provided the basic content for the large Catechism, which appeared in April 1529, and for the Small Catechism, which appeared one month later.

Teaching materials had been used in the early church for over a thousand years to prepare people for Baptism.  The Creed, the Lord’s Prayer, and the Ten Commandments were always including for study.  Although many other topics had been added to the materials over the years, Luther chose to include these three and the Sacraments of Baptism and Holy Communion, together with Confession, in his catechisms.  Because of his new understanding that salvation was by God’s grace alone through faith alone, he omitted studying the Ave Maria and the other sacraments of the Roman Catholic Church.

His catechisms have been called “the Bible in miniature” because they helped pastors, teachers, and parents explain the teachings of Scripture.  He advised that people be asked to answer questions from the catechism when they announced that they wanted to receive Holy Communion.  In the years following the Diet of Augsburg, Luther continued to encourage pastors and teachers to study the catechism and to use it in their work.  The pastors that he trained at the University of Wittenberg all had to study the catechism during their time of study.

Following the Diet of Augsburg, Luther and his friends continued to translate the Old Testament into German.  So after completing his translation of the New Testament in early 1522, he had begun work on the Old Testament.  Since Luther was not a Hebrew scholar, he received help from Melanchthon, Amsdorf, and Aurogallus, the Hebrew professor at Wittenberg.  Various parts of the Bible were printed as he finished them.  At the Coburg he worked on the prophets Jeremiah and Ezekiel.  The complete German Bible was finally printed in 1534.  Many woodcuts picturing Bible stories and beautifully illuminated initials were included in this edition.

This Bible quickly replaced the various Bibles being used in the churches at the time.  The German translation made the people feel as if the characters in the Bible were talking to them in their everyday language.  Luther’s German Bible was used extensively in church services and in homes, and so it became Luther’s crowning achievement.

Almost immediately after its printing, however, Luther began revising and improving it.  He gathered together scholars to examine details and improve wording.  He was determined that the German Bible carry God’s message accurately.  He conducted many meetings to check its accuracy.  He conducted many meetings to check its accuracy; once he had several rams killed so that the local butcher could tell him the proper name for each part of the animal.  The Wittenberg scholars who worked with him consulted Latin, Greek, and Hebrew texts.

In 1531 16 scholars helped him revise the translation of the psalms.  A revised German Bible was issued in September 1541.  Other groups checked the accuracy of the work several times, the last tie in 1544.  In all of this work, Luther was master both in leading the group and in knowing and using the various languages.