योगवासिष्ठः yogavāsiṣṭhaḥ - book-7, chapter-210, verse-24

तत्र जाग्रन्न च स्वप्नो न सुषुप्तं न चेतरत् ।
किमपीत्थमिदं भानं खमात्रं मौनमोमलम् ॥ २४ ॥

tatra jāgranna ca svapno na suṣuptaṃ na cetarat ,
kimapītthamidaṃ bhānaṃ khamātraṃ maunamomalam 24

24. There is no waking, sleeping or dreaming, nor any other condition of being, in the Turiya or transcendent state of Brahma [as in those of the divine hypostases of Brahma, Virat and others]. It is something as the pure and primeval light and as the transparent air, all quiet and still, [as the infinite eternity].