O Vidura, while searching in that way about his existence, Brahmā reached his ultimate time, which is the eternal wheel in the hand of Viṣṇu and which generates fear in the mind of the living entity like the fear of death.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
तमस्यपारे विदुरात्मसर्गं विचिन्वतोऽभूत्सुमहांस्त्रिणेमिः । यो देहभाजां भयमीरयाणः परिक्षिणोत्यायुरजस्य हेतिः
tamasyapāre vidurātmasargaṃ vicinvato'bhūtsumahāṃstriṇemiḥ | yo dehabhājāṃ bhayamīrayāṇaḥ parikṣiṇotyāyurajasya hetiḥ
SB 3.8.20