Srimad Bhagvata Mahapurana: Book 10: Chapter 1: Verses 62-69
"Whatever cowherds there are in Vraja, the foremost of whom is Nanda, and again (all) those who are their wedded wives, the Vrsnis led by Vasudeva, and Yadava women headed by Devaki, nay, (even) the kinsmen, relatives and friends of both Nanda and Vasudeva, who are devoted to Kamsa (yourself) are all for the most part gods themselves." This was what the all-powerful sage Narada communicated to Kamsa, going to him (of his own accord), and also apprized him of the endeavours (of Brahma and the other gods) for the destruction of the Daityas, that constituted a burden to Mother Earth, O Pariksit (a scion of Bharata)! Believing the Yadus to be (so many) gods, and Lord Visnu as about to appear from the womb of Devaki for the purpose of slaying him, and binding Devaki and Vasudeva with fetters in their own residence after the departure of the (celestial) sage, Kamsa did to death every son of the said couple even as he was born, suspecting him to be the (birthless) Visnu (Himself). Greedy monarchs given to self-gratification on this earth generally, as a matter of fact, kill their (own) father and mother, brothers as well as all their relations. Knowing himself to have been, in a previous existence, the great demon Kalanemi, slain by Visnu and reborn (as Kamsa) in current life, he entered into hostilities with the Yadus. Nay, putting in prison his (own) father, Ugrasena-the lord of the Yadus, the Bhojas and the Andhakas-the mighty Kamsa ruled over the Surasena territory himself.
Thus ends the first discourse, forming an introduction to the descent of Lord Sri Krsna, in the first half of Book Ten of the great and glorious Bhagavata-Purana, otherwise known as the Paramahamsa-Samhita.