Shiva Purana
अव्यक्तं कारणं यत्तत्त्रिगुणं प्रभवाप्ययम् ॥ प्रधानं प्रकृतिश्चेति यदाहुस्तत्त्वचिंतकाः ॥ ३२ ॥
The unmanifest is the cause. It consists of three Guṇas. It is the source of origin and the place of merger. It is called Pradhāna and Prakṛti by philosophers.
english translation
avyaktaM kAraNaM yattattriguNaM prabhavApyayam ॥ pradhAnaM prakRtizceti yadAhustattvaciMtakAH ॥ 32 ॥
hk transliteration by Sanscript