Hylander and Mark,
I value your opinions on this topic.
In Book III, the Sibyl explains how she gets and makes her prophecies:
{I say} these things to you, having left the long Babylonian walls of Assyria, frenzied, a fire sent to Greece, prophesing the disclosures of God to all mortals, so that I prophesy divine riddles to men. … But when everything comes to pass, then you will remember me and no longer will anyone say that I am crazy, I who am a prophetess of the great God. … God put all of the future in my mind so that I prophesy both future and former things and tell them to mortals. … all the latter things have been revealed, so let all these things from my mouth be accounted true.
The implication seems to be that God puts ideas in some prophets’ heads and this is the origin of their prophecies. They are in a frenzy and have ideas in their heads about the future and the ideas are their prophecies when they speak them.
But of course, the fact that the Sibyl in the poem described her oracle this way doesn’t mean that it actually occurred in that fashion. Maybe some ancient readers imagined that she “miraculously” or “inspirationally” produced her utterances in exactly the form of hexameter while in a frenzied state.
The Study Light page on the Sibylline Oracle says that Justin Martyr
argues that Plato must have had this Sibyl [the Roman one at Cumae, Italy] in his mind when he described in the Phaedrus (244B) and the Meno (99C) the phenomena of prophetic frenzy or rapture, since the Sibyl did not recollect afterwards what she had said during her unconscious ecstasies.
[Note: In the Sibylline oracles, the Sibyl is passive or reluctant under the influence of inspiration. This tallied with some Jewish and Christian conceptions of prophetic inspiration…]
SOURCE: Sibylline Oracles - Hastings’ Dictionary of the New Testament - Bible Dictionary
What do you think of Justin Martyr’s description of how the prophecying worked?
Justin writes:
And Plato, when he read her oracles, seems to me to have regarded the reciters of oracles as divinely inspired. For he saw that the things which had been spoken of old by her were actually fulfilled; and therefore in the dialogue with Meno [1. Plato, Meno, 99.], expressing admiration and eulogy of the prophets for their sayings, he has thus written: "We might truly name as divine those whom we call prophets. Not least should we say that they are divine and profoundly inspired and possessed of God when they truly speak of many and great matters, knowing nothing of the things of which they speak; "clearly and obviously referring to the oracles of the Sibyl. For she was unlike the poets, who after the writing of their poems have power to correct and polish, especially the accuracy of the meters, but at the time of her inspiration she was filled with the matters of her prophecy, and when the spell of inspiration ceased her memory of the things spoken also ceased. This accordingly is the reason why all the meters of the verses of the Sibyl have not been preserved. For we ourselves, being in the city, learned from the guides who showed us the places in which she uttered her oracles that there was also a vessel made of bronze in which they said her remains were preserved. And besides all other things which they narrated, they also told us this, as having heard it from their forefathers, that they who received the oracles at that time, being without education, often utterly missed the accuracy of the meters, and this they said was the reason for the want of meter in some of the verses, the prophetess after the ceasing of her possession and her inspiration having no remembrance of what she had said, and the writers having failed for want of education to preserve the accuracy of the meters. Therefore it is evident that Plato said this about the reciters of oracles in reference to the oracles of the Sibyl; for he thus said: “When they truly speak of many and great matters, knowing nothing of the things of which they speak.”
https://www.sacred-texts.com/cla/sib/sib15.htm