Śrī brahma-saṁhitā 5.12
āpas tasmāt sanātanāt
yoga-nidrāṁ gatas tasmin
sahasrāṁśaḥ svayaṁ mahān
nārāyaṇaḥ — named Nārāyaṇa; saḥ — that; bhagavān — Supreme Personality of Godhead, Mahā-Viṣṇu; āpaḥ — water; tasmāt — from that; sanātanāt — eternal person; āvirāsīt — has sprung; kāraṇa-arṇaḥ — the Causal Ocean; nidhiḥ — expanse of water; saṅkarṣaṇa-ātmakaḥ — the subjective portion of Saṅkarṣaṇa; yoga-nidrām gataḥ — in the state of deep sleep; tasmin — in that (water); sahasra-aṁśaḥ — with thousands of portions; svayam — Himself; mahān — the Supreme Person.
The same Mahā-Viṣṇu is spoken of by the name of "Nārāyaṇa" in this mundane world. From that eternal person has sprung the vast expanse of water of the spiritual Causal Ocean. The subjective portion of Saṅkarṣaṇa who abides in paravyoma, the above supreme puruṣa with thousands of subjective portions, reposes in the state of divine sleep [yoga-nidrā] in the waters of the spiritual Causal Ocean.
Yoga-nidrā (divine sleep) is spoken of as ecstatic trance which is of the nature of the bliss of the true subjective personality. The above-mentioned Ramādevī is yoga-nidrā in the form of Yogamāyā.