Theophilus of Antioch believed that the prophets, in contrast with the poets and philosophers, were “possessed by a holy Spirit” (πνευματοφόροι πνεύματος ἁγίου) and were inspired and taught by God. Because they were righteous persons, the Lord saw fit to use them to receive his Wisdom. This Wisdom enabled them to speak of such matters as creation and coming calamities (II.9). Theophilus believed that not only the Hebrew prophets were so inspired, but also “the Sibyl among the Greeks” (II.9; ἀλλά καὶ παρὰ ̔Ελλησιν Σίβυλλα). All of persons possessed by the Spirit have spoken a consistent message, and, because their prophecies of events now passed came true, one may have confidence that the ones yet to be fulfilled will “prove correct” as well (II.9).
Later he writes, “All these things are taught us by the Holy Spirit which spoke through Moses and the other prophets; so that the books which belong to us, the worshippers of God, are proved to be writings not only more ancient but also more true than all historians and poets” (II.30).
Theophilus also encourages Autolycum, to whom he is writing, to study the Scriptures for himself to find their truth. He says, “It is plain that all the rest were in error and that only the Christians have held the truth–we who are instructed by the Holy Spirit who spoke in the holy prophets and foretold everything. Furthermore, you must devotedly search the things of God, I mean those spoken through the prophets, so that by comparing what is said by us with what is said by the others you will be able to discover the truth.” (II.33-34).
Finally, he references Paul and concludes, “It is obvious how agreeably and harmoniously all the prophets spoke, making their proclamation by one and the same Spirit [1 Cor 12:11] concerning the sole rule of God and the origin of the world and the making of man” (II.35).
All citations come from Ad Autolycum (trans. R. Grant; New York: Oxford, 1970).