Shiva Purana
यतो वाचो निवर्तंते अप्राप्य मनसा सह॥ तदेव परमं प्रोक्तं ब्रह्मैव शिवसंज्ञकम्॥ १४॥
That great Brahman Śiva is said to be that from which all words return along with the mīnd, unable to attain it.
english translation
yato vAco nivartaMte aprApya manasA saha॥ tadeva paramaM proktaM brahmaiva zivasaMjJakam॥ 14॥
hk transliteration by Sanscript