H.W. Parke in the foreword to his 1967 book Greek Oracles presents oracles as the Greek and Roman equivalent to the Jewish or Christian Bible. While certain texts had come to be viewed with a certain authority, and even a level of divine inspiration (Homer and Plato for example), for Parke, “in spite of this the Greeks and Romans did not use the works of Homer in the way in which Christians use their bible.” Rather, “To the Greek or Roman who sought the word of god on some particular issue the normal step would not be to consult a book but to enquire from a prophet.”
It is unclear whether this is a comparison he intends to make for the ancient world. I get the impression that the real contrast he is making is between ancient Greeks and modern Christians in their use of the Bible, but it does raise interesting questions about the role of oracles and sacred texts in the ancient world and early Christianity in particular. The first thing to acknowledge when bringing this comparison into the ancient world is that things are not nearly so clean-cut as the comparison suggests. Greek oracles, for instance, were not purely oral phenomena, but were often written down and brought into larger collections such as the Sibylline books at Rome, and other various collections attributed to seers of the legendary past, thus giving them a textual character more akin to a Jewish or Christian Bible. It is also not as if early Christians were without their own prophets who operated alongside their reading of scriptural texts.
What I want to focus on is Parke’s point about function: Is the early Christian use of scripture analogous to the way oracles were used in the wider Mediterranean world? One fairly obvious way in which this is so is when scriptural texts and oracles were seen to predict, or speak about future events; often ones that are fulfilled in the interpreter’s own day. But oracles did not only foretell the future. I would like to draw attention to just one other way that oracles and scripture were put to similar use, which is to derive information about the general nature and character of the gods.
Dio Chrysostom, in his seventeenth oration, On Covetousness, recalls an oracle given to the Spartans when they asked if Arcadia had been given to them. The reply, “Nay, give it I’ll not!” demonstrates for Dio that “the god…by his very nature punishes the covetous” (Or. 17.16). Thus, he uses both the words of the oracle, and the situation in which it was given, to draw a conclusion about the nature and habitual action of the gods with which he warns his audience against covetousness. Plutarch, in his Life of Numa, also wants to make the general point that it is possible and indeed proper that a god should harbour affection and love for particular people based on their character and virtues. Among other examples, he cites the story that whenever Hippolytus would set sail towards Delphi, the Pythia would chant, ““Lo, once more doth beloved Hippolytus hither make voyage” (Numa 4.5). Plutarch takes this as illustrative of the joy with which Apollo awaited his arrival, and thus demonstrative of the character of the god.
Paul can be seen to take the same interpretative posture towards the Exodus narrative in Romans 9.14-18 when he is defending God against the charge of injustice. His basic point is expressed in v. 18, “So then he has mercy on whomsoever he chooses, and he hardens the heart of whomsoever he chooses” (NRSV). This is inferred from two quotes in Exodus 33.19 and 9.16 addressed to Moses and Pharaoh respectively: “I will have mercy on whom I have mercy, and I will have compassion on whom I have compassion,” and “I have raised you up for the very purpose of showing my power in you, so that my name may be proclaimed in all the earth.” Like the earlier examples referred to, Paul derives his knowledge of the character and habitual actions of God both from the words attributed to him, and the situation in which they were given (Paul names both Moses and Pharaoh as the recipients of God’s words). Christopher Stanley remarks how Paul conducts his argument at this point “at the level of broad principles.” These are not predictions, but past exchanges that reveal the nature of God and his dealings with people. In this way Paul’s argument bears witness to one more way in which both Greek oracles and Jewish scriptures can be seen as occupying the same space within the culture of the time, that of preserving and communicating the words of a god.
 H. W. Parke, Greek Oracles (London: Hutchinson & Co, 1967), 9-10.
 For a recent argument that many Roman-era writers saw the Jewish scriptures as essentially oracle collections of this sort see Heidi Wendt, “Entrusted with the Oracles of God: The Fate of the Judean Writings in Flavian Rome,” in A Most Reliable Witness: Essays in Honor of Ross Shepard Kraemer, ed. Susan Ashbrook Harvey et al. (Providence, RI: Brown Judaic Studies, 2015).
 One need only think of the many oracles “uttered long ago” that Thucydides reports were being circulated in the Peloponnesian War (Thuc. 2.21.3; 2.54.2; 5.26.4.), the ambiguous oracle Josephus mentions that predicted a Judean would rule the world (War 6.311.), or Matthew’s fulfilment formula that events in Jesus’ life happened to fulfil the prophecies of Hebrew prophets (Matt. 1.22-23; 2.15, 17-18, 23.).
 Christopher D. Stanley, Arguing with Scripture: The Rhetoric of Quotations in the Letters of Paul (New York: T&T Clark International, 2004), 156.