Shiva Purana

siva.sh/siva-purana/saturda-samhita/8/56

परब्रह्म शिवः साक्षात्सच्चिदानन्दलक्षणः ।। परमात्मा गुणातीत इति ज्ञानमवापतुः ।। ५६ ।।

sanskrit

But they realised that Śiva is the Supreme Brahman with Sat (Existence) Cit (knowledge) and Ānanda (Bliss) as the characteristics. He is the great Ātman and transcends the attributes.

english translation

parabrahma zivaH sAkSAtsaccidAnandalakSaNaH || paramAtmA guNAtIta iti jJAnamavApatuH || 56 ||

hk transliteration by Sanscript