Bhagavatapurana 5.23.8

5.23.8

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etad u haiva bhagavato viṣṇoḥ sarva-devatāmayaṃ rūpam aharahaḥ sandhyāyāṃ prayato vāgyato nirīkṣamāṇa upatiṣṭheta namo jyotir-lokāya kālāyanāyānimiṣāṃ pataye mahā-puruṣāyābhidhīmahīti //

8. This indeed a manifestation of the glorious Vishnu in which all the gods find their place. One should piously and silently see that form every evening and worship it with the following Mantra. We bow to the one abode of light, the wheel of Time (Kalachakra), the protector of the gods, the Supreme Person. We contemplate Thee.