PURPORT

Lord Sri Krsna was invited by Maharaja Yudhisthira to look into the supervision of the performances of yajna, and the Lord, to abide by the orders of His elderly cousin, caused the performance of yajnas by learned twice-born brahmanas. Simply taking birth in the family of a brahmana does not make one qualified to perform yajnas. He must be twice born by proper training and initiation from the bona fide acarya. The once-born scions of brahmana families are equal with the once-born sudras, and such brahma-bandhu or unqualified once-born scions must be rejected for any purpose of religious or Vedic function. Lord Sri Krsna was entrusted to look after this arrangement, and perfect as He is, He caused the yajnas to be performed by the bona fide twice-born brahmanas for successful execution.