Shiva Purana
प्रत्ययान्तरनिर्मुक्तः प्रवाहो ध्यानमुच्यते ॥ सर्वमन्यत्परित्यज्य शिव एव शिवंकरः ॥ ५३ ॥
The flow freed from the interference of belief is called meditation. Leaving aside everything else, Shiva is the Shivankara.
english translation
pratyayAntaranirmuktaH pravAho dhyAnamucyate ॥ sarvamanyatparityajya ziva eva zivaMkaraH ॥ 53 ॥
hk transliteration by Sanscript