Mahabharata 5.103.35

प्रत्यक्षो ह्यस्य सर्वस्य नारदोऽयं महातपाःमाहात्म्यं यत्तदा विष्णोर्योऽयं चक्रगदाधरः

pratyakṣo hyasya sarvasya nārado'yaṃ mahātapāḥmāhātmyaṃ yattadā viṣṇoryo'yaṃ cakragadādharaḥ

Our plain-language meaning of this verse is waiting for scholar review.