Muilenburg, James. "Chapter Five: Employment of Scripture." The Literary Relations of the Epistle of Barnabas and the Teaching of the Twelve Apostles. Marburg, 1929, 85-97.
Muilenburg considers the Old Testament usage in Barnabas to be "profuse" and similar in nature to the patterns found in Philo of Alexandria (Muilenburg 1929, 85). He uses it as his authoritative source of proof for arguments. While he mostly uses the wording of the Septuagint, he also feels free to make alterations in wording so as to expose what he considers the true significance. Muilenburg provides several examples of uses of the Old Testament in which Barnabas is faithful to essential ideas but not to specific wording (Muilenburg 1929, 86-87). The type of exegesis used suggests to Muilenburg a familiarity with the Hebrew Old Testament and a rabbinic approach to symbolic and allegorical interpretation (Muilenburg 1929, 88-89). Because of the type of Old Testament usage, and the lack of clearly Gnostic elements despite extensive references to γνῶσις, Muilenburg, with Harnack, takes the text to be dated about 130, and to stem from Alexandria (Muilenburg 1929, 90).
The Didache also has a large amount of quotation and paraphrase of Scripture. However, unlike Barnabas, the Didache mostly seems drawn from the New Testament (Muilenburg 1929, 91). Muilenberg identifies eight quotations, discussing some of them in detail (Muilenburg 1929, 91ff). A challenge in analysis is the terse style of the Didache, which results in truncated quotations. Mulienburg discusses the variations in language and briefly entertains the possibility of an early date of composition, but then suggests "8:2, 15:3, and 15:4 seem rather to imply a written record" (Muilenburg 1929, 93). He does not explain what makes that implication. Muilenburg notes that Harnack finds as many as 23 places where the Didache uses the New Testament, with 17 of them from Matthew (Muilenburg 1929, 9). Muilenburg considers many passages to show traces of New Testament content, but notto be very clear.
Muilenburg concludes that the use of biblical texts is very different in the Didache and Barnabas, and that neither author seems to know or directly use the other (Muilenburg 1929, 96-97).