What is it? And, more importantly, why should anyone care? Well, for one thing, it just might explain how and why Paul uses the OT in the way that he does.
Prosopological exegesis (PE) is a technique of interpreting Scripture common in the early church. As Matthew W. Bates describes it, PE “explains a text by suggesting that the author of the text identified various persons or characters (prosopa) as speakers or addressees in a pre-text, even though it is not clear from the pre-text itself that such persons are in view” (The Hermeneutics of the Apostolic Proclamation, 183). By “text,” Bates refers to “any specific instance in which a NT author, such as Paul, directly cites the scriptures” (53), while a “pre-text” means “a specific textual source that the NT author utilized” (54). Thus, when Paul cites Hab 2:4b LXX in Rom 1:17, Rom 1:17 is the text and Hab 2:4b LXX is the pre-text.
According to Bates, the first study of the use of PE in the early church was carried out by the German scholar Carl Andresen in his article “Zur Entstehung und Geschichte des trinitarischen Personbegriffes,” ZNW 52 (1961): 1-39. Andresen’s interest was piqued by Tertullian’s commentary on Gen 1:26 (“let us make man in our image”), which he understood as God the Father speaking to God the Son. Tertullian (Adv. Prax. 11-13) found evidence of various members of the Trinity addressing one another throughout the OT, even in prophecies such as Isa 45:14-15, which appears to be addressed to a generic audience and not to Christ. Thus, “Tertullian believes that the prophet can speak in this manner in the words of a persona (or prosopon) not explicitly in view in the source text” (Proclamation, 186). This was not an invention of Tertullian or even of Christians more broadly (e.g., Justin Martyr, 1 Apol. 36.1-2); instead, it was in fact somewhat common within pagan literary criticism, drama, and rhetoric (e.g., Heraclitus), as well as contemporary Jewish literature (e.g., Philo).
Surveying all of this literature, Bates comes up with the following technical definition for PE: “Prosopological exegesis is a reading technique whereby an interpreter seeks to overcome a real or perceived ambiguity regarding the identity of the speakers or addressees (or both) in the divinely inspired source text by assigning nontrivial prosopa (i.e., nontrivial vis-à-vis the “plain sense” of the text) to the speakers or addressees (or both) in order to make sense of the text” (Proclamation, 218).
Bates identifies the following four criteria for detecting PE within ancient literature (219-20):
(1) Speech/dialogue: the pre-text must involve a person who is speaking.
(2) Nontriviality of person: the speaker in the pre-text must be ambiguous or not identified.
(3) Introductory formulas or markers: the exegete usually (but not always) indicates in the text who (s)he believes the speaker to be.
(4) Intertextual evidence: especially in the case where (3) is absent, if contemporary or later texts use PE to interpret a given pre-text, it is more likely that the text under consideration is also using PE when interpreting the same pre-text. Bates seems to be particularly interested in this application of reception history.