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.
These foundational methodological tenets in place, this paper now considers several overarching historical-critical methodological points. Writ large, these criterion stem from the importance of understanding an ancient work in as much context as possible. Consideration of availability, accessibility, genre, language, and prior attribution remain standard considerations for any historically-oriented study. In addition to these contexts, oral tradition, memory, and textual fluidity constitute additional aspects of the ancient world worthy of attention when dealing with the retrieval of sources. By themselves, these general historical-critical concerns reveal little about specific uses of one text in another. They do indicate, however, the need for nuance, caution, and contextualization before digging into the complexities of the ancient world.
Availability: The criteria of availability rather commonsensically indicates that texts may only employ sources which were already in existence. Of critical importance is the accurate determination of when a text was written. For example, the possible use of Titus 3:1 (πρὸς πᾶν ἔργον ἀγαθὸν ἑτοίμους εἶναι) in 1 Clement 2:7 (ἕτοιμοι εἰς πᾶν ἔργον ἀγαθόν) largely hinges upon when one believes the Pastoral Epistles were written. The availability criteria also suggests that a text’s failure to use a source may not demonstrate that the earlier text was not available.
Accessibility: Not only does a source need to be available in order to be used, but it must also be accessible. That is, not only need a text exist, but it also needs to be popular (or valuable) enough to read and reuse. For example, the Pentateuch was widely accessibly during the lifetime of the Apostle Paul, and thus we may readily posit his use of Torah in his letters. Conversely, we may not necessarily presume that Paul’s letter to Philemon was accessible to the author of the Acts of Paul, even though we have ample reason to believe that Philemon was written before the Acts. The accessibility criteria gains support when other contemporaneous or local texts—or even the text examined—demonstrate knowledge of a possible source.
 Discussions of late antique literature, especially modern Biblical Studies and Early Christian Studies, have regularly invoked the importance of context. Collingwood’s The Idea of History succinctly highlights the importance of context: “Thinking is never done in vacuo: it is always done by a determinate person in a determinate situation.” Cited in Peter Burke, “Context in Context,” Common Knowledge 8.1 (2002): 162. Stuhlhofer, 244-9. Andreas Kostenberger and Michael Krueger, The Heresy of Orthodoxy: How Contemporary Culture’s Fascination with Diversity Has Reshaped Our Understanding of Early Christianity (Wheaton: Crossway Publishers, 2010), 144. Burke, 153-5, 172. See also Richard Rorty, “Inquiry as Recontextualisation,” reprinted in Objectivity, Relativism and Truth (Cambridge: Cambridge University Press, 1991), 93-110.  Hays, Echoes, 29. Allison, The New Moses, 19.  For a highly skeptical position on the possibility of accurately dating biblical texts, see Lyle Eslinger, “Inner-Biblical Exegesis and Inner-Biblical Allusion: The Question of Category,” VT 42 (1992): 52, 56-8.  Novum Testamentum Graece, Nestle-Aland 28. Online: Deutsche Bibelgesellschaft, 2015. Hereafter NA 28.  Ehrman, 38.  Andrew F. Gregory and Christopher M. Tuckett, “Reflections on Method: What constitutes the Use of the Writings that later formed the New Testament in the Apostolic Fathers?” in The Reception of the New Testament in the Apostolic Fathers (ed. C.M. Tuckett and A.F. Gregory, Oxford: OUP, 2005), 62.  Hays, Echoes, 30. Thompson, 30-7.  Gregory and Tuckett, 65. On the definition and acceptance of the Old Testament as scripture and canon in the early Church, see Ellis’s summary (E. Earle Ellis, “The Old Testament Canon in the Early Church” in Mikra: Text, Translation, Reading and Interpretation of the Hebrew Bible in Ancient Judaism and Early Christianity [ed. M.J. Mulder and H. Sysling, Philadelphia: Fortress, 1988], 653-79.).  Harry Y. Gamble, “The Book Trade in the Roman Empire” in The Early Text of the New Testament (ed. C.E. Hill and M.J. Kruger, Oxford: OUP, 2012), 33. While many ancient writings followed a slow-growth model, certain Christian texts appear to have gained wide circularity quite quickly. See John Barton, Holy Writings Sacred Text: The Canon in Early Christianity (Louisville: Westminster John Knox Press, 1997), esp. 94. Kostenberger and Kruger, 198-201. David Trobisch, Die Entstehung der Paulusbriefsammlung: Studien zu den Anfangen christlicher Publizistik (Gottingen: Vandenhoeck & Ruprecht, 1989).  Stuhlhofer, 249-50.