Virgil, Aeneid 6.98-101
talibus ex adyto dictis Cumaea Sibylla
horrendas canit ambages antroque remugit,
obscuris vera involvens: ea frena furenti
concutit et stimulos sub pectore vertit Apollo.
With such words from her sanctuary the Sibyl of Cumae sings her terrifying ambiguities and re-echoes from her cave, wrapping up the truth in obscurity. Apollo agitates her reins as she rages, and turns his spurs beneath her chest.