योगवासिष्ठः yogavāsiṣṭhaḥ - book-7, chapter-63, verse-5

तदेन्दुकार्ष्ण्यखतनुशिलागेयादितां गताः ।
इवाभान्ति चिदाकाशास्तथा देहरवादयः ॥ ५ ॥

tadendukārṣṇyakhatanuśilāgeyāditāṃ gatāḥ ,
ivābhānti cidākāśāstathā deharavādayaḥ 5

5. The clear sky of the intellect, is darkened by its imageries (ideas), like the disk of the moon by its blackness, and as the body (face) of the sky by its clouds; but these are as false as the song of a stone, and the sound of a dead body.