Shiva Purana

siva.sh/siva-purana/saturda-samhita/8/21

विधिविष्णू ऊचतुः।। वेदाः प्रमाणं सर्व्वत्र प्रतिष्ठा परमामिताः।। यूयं वदत विश्रब्धं किमेकं तत्त्वमव्ययम्।। २१।।

sanskrit

Brahmā and Viṣṇu said:— Vedas are the authorities everywhere. They have been honoured everywhere. Hence you please say unreservedly. What is the sole unchanging entity?

english translation

vidhiviSNU UcatuH|| vedAH pramANaM sarvvatra pratiSThA paramAmitAH|| yUyaM vadata vizrabdhaM kimekaM tattvamavyayam|| 21||

hk transliteration by Sanscript