व्यासप्रसादाच्छ्रुतवानेतद्गुह्यमहं परम्।
योगं योगेश्वरात्कृष्णात्साक्षात्कथयतः स्वयम्।।18.75।।
।।18.75।। व्यास जी की कृपा से मैंने इस परम् गुह्य योग को साक्षात् कहते हुए स्वयं योगोश्वर श्रीकृष्ण भगवान् से सुना।।
The phrase vyasa-prasadat means by the grace of Krishna Dvaipayana Vedavyasa the author of Vedanta Sutras, the Puranas, Mahaharata, etc. This grace gave Sanjaya celestial vision and clairaudience to directly see and hear all that transpired on the battlefield and thus he was able to recite verbatim the divine discourse spoken by Lord Krishna known as Srimad Bhagavad-Gita exactly as Lord Krishna originally revealed it.
