That illustrious Rishi, having divided by his ascetic power the Vedas into four parts, has become known on earth as Vyasa and for his black colour as Krishna.
यो व्यस्य वेदांश्चतुरस्तपसा भगवानृषिः। लोके व्यासत्वमापेदे कार्यात् कृष्णत्वमेव च॥