Shiva Purana
देवो गुणत्रयातीतः सर्वज्ञः सर्वकृत्प्रभुः ॥ ओमित्येकाक्षरे मन्त्रे स्थितः सर्वगतः शिवः ॥ ८ ॥
The omniscient lord, the creator of everything, the all-pervasive Śiva who is beyond the three attributes, is stationed in the single-syllabled mantra Om.
english translation
devo guNatrayAtItaH sarvajJaH sarvakRtprabhuH ॥ omityekAkSare mantre sthitaH sarvagataH zivaH ॥ 8 ॥
hk transliteration by Sanscript