Bhagavatapurana 10.3.8

10.3.8

niśīthe tama-udbhūte jāyamāne janārdane /
devakyāṃ deva-rūpiṇyāṃ viṣṇuḥ sarva-guhā-śayaḥ /
āvirāsīd yathā prācyāṃ diśīndur iva puṣkalaḥ //

8. At mid-night, in the thickest darkness, Vishnu who dwells in every heart, revealed Himself, in His full glory like the full moon in the East, in His own supreme divine form, out of Devaki who was like unto a goddess, at a time when the people were being put to greatest afflictions.