Muilenburg, James. "Chapter Seven: Literary Integrity." The Literary Relations of the Epistle of Barnabas and the Teaching of the Twelve Apostles. Marburg, 1929, 109-139.
Muilenburg reviews theories in which Barnabas is seen to have been heavily interpolated (Muilenburg 1929, 109). His view is that it shows literary unity but a greater breadth of ideas than criticis wish to admit. Muilenburg takes an analysis of th,e Two Ways passage to illustrate the literary unity of Barnabas. Attempts to analyze the passage in terms of a series of interpolations prove to create enough logical gaps that Muilenburg does not find them plausible. He illustrates this by discussing the theoretical classification if Windisch (1920) in detail (Muilenburg 1929, 110ff).
A significant unifier, in Muilenburg's estimation, is the use of transition sentences (Muilenburg 1929, 113). They tend to emphasize the importance of γνῶσις, and treat knowing as a recurring theme throughout all 21 chapters. Both the first portion (ch. 1-17) and the second (18-21) are tied together by the theme. "Walking" in the way of righteousness and such knowledge is an essential part of the entirety of the teaching (Muilenburg 1929, 114). Muilenburg illustrates this with numerous sentences pulled from the text. The picture he develops is that of an author who reiterates ideas so as to make internal references to the same topic throughout a work. Muilenburg further notes consistent references to Isaiah and to Ephesians, again, spread throughout the Epistle (Muilenburg 1929, 119, 1212). Muilenburg's analysis is lengthy and detailed.
In conclusion, based on internal evidence, Muilenburg concludes that the same author is responsible for chapters 1-17 and 18-20. The portions of chapter 19 which are sometimes thought to be an insertion are drawn from earlier chapters in a way similar to the other portions of the text (Muilenburg 1929, 130).
Muilenburg continues by analyzing the Epistle's 21st chapter to see if there is a divergence from the prior patterns (Muilenburg 1929, 130ff). In fact, again, as he walks through the material line by line, he finds consistency in themes, self-referential statements, and manner of expression.
Muilenburg briefly considers whether the Didache shows integrity in its composition (Muilenburg 1929, 135ff). He finds the same compositional techniques in operation in 1-6 and in 7-16, including methods of abridging sources, simplicity of expression, and overall catecetical purpose (Muilenburg 1929, 136). While the Didache has literary unity, Muilenburg is quick to define that unity. "Literary unity of the Teaching means, briefly, that the compilation is the work of one hand" (Muilenburg 1929, 137). He does conclude that the work is composite in nature. Muilenburg provides samples of internal statements and reviews which point up the careful work of creating literary unity and consistency throughout the work. While Muilenburg does not define a date, he suggests the work comes from the time of Barnabas or earlier (Muilenburg 1929, 139).