O King, Lord Śiva, Nārada the sage amongst the demigods, and Kapila, the incarnation of Godhead, all know very confidentially about His glories through direct contact.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
अस्यानुभावं भगवान् वेद गुह्यतमं शिवः । देवर्षिर्नारदः साक्षाद्भगवान् कपिलो नृप
asyānubhāvaṃ bhagavān veda guhyatamaṃ śivaḥ | devarṣirnāradaḥ sākṣādbhagavān kapilo nṛpa
SB 1.9.19