Śrī Caitanya Mahāprabhu has advised to associate with this class of men, hankering after money and women, it is better . . . death is better, preferred, than to associate. When He was requested to see King Pratāparudra—because he was king, he's supposed to be always in association with money and women—He refused to see him: "No, I cannot see the King." When He refused to see, He quoted one verse: bhava-sāgarasya, niṣkiñcanasya bhava-sāgarasya. Niṣkiñcanasya jigamiṣor bhava-sāgarasya (CC Madhya 11.8).
People do not know what is bhava-sāgara. They do not know even. But in Vedic literature, this is the first instruction, how to get out of this bhava-sindhu, bhava-sāgara, material ocean. The whole universe is also a ocean. And all these planets, they are called dvīpa. Just like this planet is called Jambudvīpa, Bhārata-varṣa. Actually it is like dvīpa. Nowadays, those who are flying in the sky, they're going from one island to another island, one planet to another planet. So when there is called dvīpa, there must be relative term, the ocean, or the sea. So whole this universe, this planets, they are called dvīpa. Therefore they are floating in the ocean of air. Just like you have got experience. You have got experience of this also, ocean of water. And above water, there is air, ocean of air. Then there is sky.
So bhava-sāgarasya. The whole universe is bhava-sāgara. Sāgara means ocean, or sea. And bhava means repetition of birth and death.