The three questions on the Office of the Keys in the fifth chief part form the most important and independent addition to Luther's Small Catechism. However, they are not only in complete agreement with Luther's doctrine of Absolution, but, in substance, also contained in what he himself offered in the part Of Confession. For what Luther says in paragraphs 26 to 28 in a liturgical form is expressed and explained in the three questions on the Office of the Keys in a doctrinal and catechetical form. Not being formulated by Luther, however, they were not received into the Book of Concord. In the Nuernberg _Text-Booklet_ of 1531 they are placed before Baptism. Thence they were taken over into the Nuernberg _Children's Sermons_ of 1533 as a substitute for Luther's form of Confession. Andrew Osiander, in the draft of his Church Order of 1531, in the article on "Catechism and the Instruction of Children," added as sixth to the five chief parts: "Of the Keys of the Church, or the Power to Bind and to Unbind from Sins," quoting as Bible-verse the passage: "The Lord Jesus breathed on His disciples," etc. Brenz, though not, as frequently assumed, the author of the Nuernberg Catechism, also contributed toward introducing and popularizing this part of the Catechism. In his Questions of 1535 and 1536, which appeared in the Appendix to the Latin translation of Luther's Large Catechism, he offered an original treatment to the Keys of Heaven, as the sixth chief part, on the basis of Matt. 16, 19; Luke 19, 16; John 20, 22f. Thirty-six years after the first publication of Luther's Catechisms, Mathesius, in his _Sermons on the Life of Luther,_ also speaks of six chief parts of catechetical instruction; but he enumerates Absolution as the part between Baptism and the Lord's Supper, hence as the fifth chief part of the Catechism.