Mahabharata 12.336.49
व्रतिनां चापि यो धर्मः स ते पूर्वं नृपोत्तमकथितो हरिगीतासु समासविधिकल्पितः
vratināṃ cāpi yo dharmaḥ sa te pūrvaṃ nṛpottamakathito harigītāsu samāsavidhikalpitaḥ
Our plain-language meaning of this verse is waiting for scholar review.
Open in the book