Śrīmad-Bhāgavatam 3.22.20 – Kardama Muni preferred to devote his life as a servant of the Lord in paramahaṁsa knowledge and to beget a child only for that purpose, not to beget numberless children to fill up the vacancies in the universe. He knew very well, that Viṣṇu was his worshipable Deity and whatever Viṣṇu desired was his duty, and nothing else.