Poirier works hard to rehabilitate a minority reading of the key biblical verse 2 Timothy 3:16, arguing that the Greek term theopneustos was not originally used in ancient Greco-Roman contexts to mean "divinely inspired," but instead meant "God-breathing" in the sense of conveying life (a la Genesis 2:7). Thus, on this reading, the author of 2 Timothy would be teaching that "all Scripture is life-giving and therefore useful for teaching, admonishing, correcting, and training in righteousness."
In his thorough and informative introduction, Poirier lays out the history of interpretation of 2 Tim 3:16. Perhaps his most helpful contribution is his demonstration of how scholarship since the 20th century has been too beholden to B. B. Warfield's flawed interpretation. Warfield tried to claim that the term theopneustos must always be passive and always referred to divine inspiration -- an argument Poirier capably refutes.
From there, Poirier attempts to demonstrate that the earliest extant examples of theopneustos and its lexical cognates outside of its single use in the New Testament are best understood in their contexts to describe something as "life-giving." For example, it can refer to: life-giving springs or streams of water (Sibylline Oracles); life-preserving ointments applied to a corpse to prevent decay (Testament of Abraham); the living or life-giving soul/breath (Valens' Anthologies); and the power of pharaohs to grant life to their subjects (as opposed to having them executed), as memorialized on a Sphinx inscription.
Since these uses of theopneustic language are roughly contemporaneous with 2 Timothy, they provide evidence to support the possibility that that biblical text was referring not to the divine inspiration of the Hebrew Bible, but rather to its ability to give life to its readers (i.e., by pointing them to the gospel of salvation in Christ -- see 2 Tim 3:15, the verse immediately preceding -- and giving instruction on how to live in light of the gospel).
Why, then, did Christian tradition come to read this verse so staunchly as implying divine inspiration? Poirier asserts that this misreading begins in the third century, with Origen of Alexandria misunderstanding the term and importing a Philonic scheme of biblical exegesis around it. Once the New Testament was then translated into Latin, with theopneustos rendered as divinitus inspirata, this reading was enshrined into the tradition.
In rejecting an inspirationist reading, Poirier seeks to return readers to what he sees as the earliest, primitive Christian understanding: that infallible truth resides not in a text (which wasn't even finished or canonized in that first generation of believers), but in the apostolic proclamation of the gospel of Jesus, which is witnessed to (imperfectly but adequately) by the Scriptures. The texts give life by conveying this gospel.
But is Poirier's case convincing?
On the whole, he succeeds in demonstrating that most instances of theopneustic language prior to the third century do, in fact, bear the connotation of something being "life-giving" (if taken in the active voice) or "living" (if passive). This makes his reading of 2 Tim 3:16 possible, but not proven.
I found his assertion of Origen being the first to misread theopneutos as "divinely-inspired" very weak. The examples he gives from Clement of Alexandria (Origin's predecessor) seem to me to be clearly inspirationist as well, and Poirier's arguments to the contrary were unconvincing. Poirier appeals to a possible indirect allusion to 2 Tim 3:16 in Irenaeus' earlier Against Heresies to support the notion that earlier church fathers described Scripture as "life-giving," but the parallel is incredibly weak. The fact is that we do not see Christian authors using theopneustos to mean anything other than divine inspiration aside from the one outlier, the fifth-century Nonnus of Panopolis.
This is not to say that Clement could not have been guilty of misinterpreting 2 Tim 3:16. However, it does at least serve as evidence that an inspirationist reading of the language is indeed very early and may even reflect a common Hellenistic Jewish and later Christian assumption about the nature of Scripture -- an assumption that may lie behind various texts of the New Testament, whether or not it is made explicit.
In terms of how to translate theopneustoc in 2 Tim 3:16, then, I think the evidence could point us in either direction. Linguistic evidence may slightly favor the rendering "life-giving," but we cannot rule out the possibility that Christians like the author of 2 Timothy were already employing the term in the now-traditional sense of inspiration. I'm left wishing we had more surviving early examples of how the term theopneustos was used to describe written texts to help us here.
That said, I heartily agree with Poirier's conclusions about the dangers of resting the gospel's reliability on the assumption that all of the Bible must be true in a thoroughgoing way; rather, the New Testament's authority "comes from the (faith-embraced) fact that the apostles told the truth about what they had witnessed" (p. 236). The possibility is thus opened for a reading of Scripture that does not assume each and every passage was directly inspired by God, yet still sees Jesus and his resurrection as the historical object of a life-giving faith, and the Bible as an accompanying source of life-giving wisdom and food for reflection/spiritual growth.
Overall, Poirier's work is a valuable and stimulating contribution to New Testament scholarship and a helpful resource for mature thinking on biblical hermeneutics.