Srimad Bhagvata Mahapurana: Book 1: Chapter 5: Verses 37-40
"Obeisance to You, O Lord Vasudeva: we meditate on You. Obeisance also to Pradyumna, Aniruddha and Sankarsana." The lord presiding over sacrifices has the divine Mantra (mystical formula) for His body and has no material form. He alone is of true insight, who worships Him uttering the name of the four forms as indicated above. O holy Brahmana, when I had thus carried out His behest, Lord Kesava blessed me with Self-Knowledge, mystic powers and loving Devotion to His feet. O sage of unlimited knowledge, pray, recount the glories of the Almighty Lord, by hearing which even the wise reach the end of their quest for knowledge. For they recognize only the chanting of such glory, and no other, as the only means of relieving the afflictions of those who are repeatedly tormented by trials andturmoils.
Thus ends the fifth discourse, forming part of the dialogue between Vyasa and
Narada, in Book One of the great and glorious Bhagavata-Purana,otherwise known as the Paramahamsa-Samhita.