Srimad Bhagavatam Canto 03, Chapter 08, Text 09

SB 3.8.9

provaca mahyam sa dayalur ukto
 munih pulastyena puranam adyam
so ’ham tavaitat kathayami vatsa
 sraddhalave nityam anuvrataya
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
The great sage Parasara, as aforementioned, being so advised by the great sage Pulastya, spoke unto me the foremost of the Puranas [Bhagavatam]. I shall also describe this before you, my dear son, in terms of my hearing, because you are always my faithful follower.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
The great sage of the name Pulastya is the father of all demoniac descendants. Once upon a time Parasara began a sacrifice in which all the demons were to be burnt to death because his father had been killed and devoured by one of them. The great sage Vasistha Muni arrived at the sacrifice and requested Parasara to stop the deadly action, and because of Vasistha’s position and respect in the community of sages, Parasara could not deny the request. Parasara having stopped the sacrifice, Pulastya, the father of the demons, appreciated his brahminical temperament and gave the blessing that in the future he would be a great speaker on the Vedic literatures called the Puranas, the supplements of the Vedas. Parasara’s action was appreciated by Pulastya because Parasara had forgiven the demons out of his brahminical power of forgiveness. Parasara was able to demolish all the demons in the sacrifice, but he considered, “Demons are so made that they devour living creatures, men and animals, but why on that account should I withdraw my brahminical qualification of forgiveness?” As the great speaker of the Puranas, Parasara first of all spoke on the Srimad-Bhagavata Purana because it is the foremost of all the Puranas. Maitreya Muni desired to narrate the same Bhagavatam be had heard from Parasara, and Vidura was qualified to hear it because of his faithfulness and his following the instructions received from superiors. So Srimad-Bhagavatam was being narrated from time immemorial by the disciplic succession, even before the time of Vyasadeva. The so-called historians calculate the Puranas to be only a few hundred years old, but factually the Puranas existed from time immemorial, before all historical calculations by the mundaners and speculative philosophers.
Srimad Bhagavatam Canto 03, Chapter 08, Text 08
Srimad Bhagavatam Canto 03, Chapter 08, Text 10