This term is used for the mysterious power which the Divine Spirit put forth on the authors of the scriptures of the Old and New Testament, in order to their composing these as they have been received by the Church of God at their hands. “All Scripture,” says an apostle, “is theopneustic. (2 Tim 3:16)”. This Greek expression, at the time when St Paul employed it, was new perhaps even among the Greeks; yet though the term was not used among the idolatrous Greeks, such was not the ease among the Hellenistic Jews. The historian Josephus, a contemporary of St Paul’s, employs another closely resembling it in his first book against Apion, when, in speaking of all the prophets who composed, says he, the twenty-two sacred books of the Old Testament,he adds, that they wrote according to the pneustia (or the inspiration) that comes from God. And the Jewish philosopher Philo, himself a contemporary of Josephus, in the account he has left us of his embassy to the emperor Caius, making use, in his turn, of an expression closely resembling that of St Paul, calls the Scriptures “theochrestoracles;” that is to say, oracles given under the agency and dictation of God. Theopneustia is not a system, it is a fact; and this fact, like every thing else that has taken place in the history of redemption; is one of the doctrines of our faith.
*From: Theopneustia - The Plenary Inspiration Of The Holy Scriptures Deduced From Internal Evidence, And The Testimonies Of Nature, History And Science by L. Gaussen, D.D., Professor Of Systematic Theology, Oratoire, Geneva