The celestial Rishi Narada got it from that Lord of universe, viz., Narayana himself, O king, with all its mysteries and abstract of details.
नारदेन सुसम्प्राप्तः सरहस्यः ससंग्रहः। एष धर्मो जगन्नाथात् साक्षान्नारायणान्नृप॥