Vaṃśānuvārṇana and the Transition to the Fourth (Upasaṃhāra) Pada
चतुर्युगसहस्रान्तमहर्यद्ब्रह्मणो विदुः / रात्रिं युगसहस्रान्तां ते ऽहोरात्रविदो जनाः
caturyugasahasrāntamaharyadbrahmaṇo viduḥ / rātriṃ yugasahasrāntāṃ te 'horātravido janāḥ
Those who know the measure of day and night declare: Brahmā’s day lasts until the completion of a thousand cycles of the four Yugas, and his night likewise lasts a thousand such cycles.