This post is part of an ongoing series formulating a methodology for tracking and understanding the variety of ways in which early Christians received and utilized Scripture.
Prior Attribution: The principle of prior attribution consults previous scholarship to see if anyone has previously recognized the textual relationship in question. The more previous readers have found a connection, the more likely the connection exists. Of course, this is far from a hard and fast rule. Scholars are fallible human beings after all. Yet this criterion does situate contemporary studies within the long historical reception of a text. As Allison notes, “If a text or series of texts has not reminded any of its earlier readers of a particular…passage, then, as so many of those readers were intent on and capable of catching even subtle allusions to the Bible, should we not be a bit skeptical? The converse also holds. If a Matthean text has turned the minds of at least some informed readers through the centuries back to a specific verse or paragraph in the Tanak, then investigation is probably in order.”
Oral Tradition: The late antique culture oral tradition often serves as an important problematizer of easy assumptions about textually-located materials. Depending on the perspective, oral cultures—where most people are illiterate and/or have access to written texts primarily through the medium of sound rather than sight—are either better or worse at retaining information accurately than literate cultures. Regardless of the level of fluidity assumed in oral tradition, oral references to written texts are typically viewed as less exact than textual references. While a widely oral culture forms an integral context for understanding the late antique world, we must remain wary of overstating the importance of this characteristic. In the first place, Walter Ong’s concept of “secondary orality”—where an author recalls a tradition previously encountered in a written medium and then reproduces it without continued visual contact with that text—suggests that one should not immediately attribute imprecision to oral recalls of written texts.
Secondly, late antique Jewish and Christian communities are widely recognized as being especially textual. While studies of late antiquity should not neglect the culture of orality, when a known source explains the wording of any reference, attribution to that source remains methodologically preferable to claiming reliance on oral or unknown sources. As Bruce Metzger argues, it is “preferable, in estimating doubtful cases, to regard variation from a canonical text as a free quotation from a document known to us than to suppose it to be a quotation from a hitherto unknown document, or the persistence of primitive tradition.”
 Hays, Echoes, 30. Allison, Intertextual, 10. Stuhlhofer, 250-1.  There are, of course, exceptions to this principle. Older or less methodologically precise works may find citations behind every corner of a text when contemporary scholars find almost none. For an example comparison of the differences between the citations located in older and newer editions of the Apostolic Fathers, see Jacob J. Prahlow, Discerning Witnesses: First and Second Century Textual Studies in Early Christian Authority (MA thesis, Winston-Salem: Wake Forest University, 2014), Appendices A and B.  Dale C. Allison, Jr., “Matthew and the History of its Interpretation,” The Expository Times 120.1 (2008): 3.  Istvan Czachesz, “Rewriting and Textual Fluidity in Antiquity: Exploring the Socio-Cultural and Psychological Context of Earliest Christian Literacy” in Myths, Martyrs, and Modernity: Studies in the History of Religions in Honour of Jan N. Bremmer (ed. J. Dijkstra, J. Kroesen, and Y. Kuiper, Leiden and Boston: Brill, 2010), 425, 430.  Kenneth E. Bailey, “Informal Controlled Oral Tradition and the Synoptic Gospels,” Asia Journal of Theology 5 (1991): 34-54. Kenneth E. Bailey, “Middle Eastern Oral Tradition and the Synoptic Gospels,” The Expository Times 106 (1994-95): 363-7. Theodore J. Weeden, “Kenneth Bailey’s Theory of Oral Tradition: A Theory Contested by Its Evidence,” Journal for the Study of the Historical Jesus 7 (2009): 3-43. James D.G. Dunn, “Kenneth Bailey’s Theory of Oral Tradition: Critiquing Theodore Weeden’s Critique,” Journal for the Study of the Historical Jesus 7 (2009): 44-62. Czachesz, 430.  Larry W. Hurtado, “Oral Fixation and New Testament Studies? ‘Orality’, ‘Performance’, and Reading Texts in Early Christianity,” NTS 60 (2014): 321-40. See also Kelly R. Iverson, “Oral Fixation or Oral Corrective? A Response to Larry Hurtado,” NTS 62 (2016): 183-200 and Larry W. Hurtado, “Correcting Iverson’s ‘Correction’,” NTS 62 (2016): 201-6.  Walter Ong, Orality and Literacy (New York: Methen & Co, 1982. Reprinted, London: Routledge, 2002), 6f.  Charles Hill remarks that, “The impracticality of checking a source, and possibly the difficulty and expense of obtaining copies of many books for one’s library, led to the widespread practice of making notebooks (υπομνηματα), florilegia, or testimony books for easier reference.” See Charles E. Hill, “’In These Very Words’: Methods and Standards of Literary Borrowing in the Second Century” in The Early Text of the New Testament (ed. C.E. Hill and M.J. Kruger, Oxford: OUP, 2012), 266. Pliny the Younger, Letters 3.5. 4QTestim. Harry Y. Gamble, Books and Readers in the Early Church: A History of Early Christian Texts (New Haven: Yale University Press, 1995), 2-11. Gamble, “Book Trade,” 23-36. On the qualities and characteristics of Pauline-era audiences, see Stanley, “Paul’s Use,” 136-44. See also William V. Harris, Ancient Literacy (Cambridge: HUP, 1989), 272, 284, 328-330.  Metzger, Canon, 73n47.