a wind of fire and fury, an earthquake in the heavens

Plato, Ion 533e-534b
For all good poets, epic as well as lyric, compose their beautiful poems not by art, but because they are inspired and possessed. And as the Corybantic revellers when they dance are not in their right mind, so the lyric poets are not in their right mind when they are composing their beautiful strains: but when falling under the power of music and metre they are inspired and possessed; like Bacchic maidens who draw milk and honey from the rivers when they are under the influence of Dionysos but not when they are in their right mind. And the soul of the lyric poet does the same, as they themselves say; for they tell us that they bring songs from honeyed fountains, culling them out of the gardens and dells of the Muses; they, like the bees, winging their way from flower to flower. And this is true. For the poet is a light and winged and holy thing, and there is no invention in him until he has been inspired and is out of his senses, and the mind is no longer in him: when he has not attained to this state, he is powerless and is unable to utter his oracles.

Synesios, Dio 1133
But their procedure is like Bacchic frenzy – like the leap of a man mad, or possessed – the attainment of a goal without running the race, a passing beyond reason without the previous exercise of reasoning. For the sacred matter (contemplation) is not like attention belonging to knowledge, or an outlet of mind, nor is it like one thing in one place and another in another. On the contrary – to compare small and greater – it is like Aristotle’s view that men being initiated have not a lesson to learn, but an experience to undergo and a condition into which they must be brought, while they are becoming fit for revelation.

Aelius Aristides, Oration 48.32
For there was a feeling as if taking hold of the God and of clearly perceiving that he himself had come, of being midway between sleeping and waking, of wanting to look, of struggling against his departure too soon; of having applied one’s ears and hearing some things as in a dream, some waking; hair stood straight, tears flowed in joy; the burden of understanding seemed light. What man is able to put these things into words? Yet if he is one of those who have undergone initiation, he knows and is familiar with them.