Srimad-Bhagavatam: Canto 12 - Chapter 1 - Verse 17
Sanskrit:
युगानि युगधर्मांश्च मानं प्रलयकल्पयो: ।कालस्येश्वररूपस्य गतिं विष्णोर्महात्मन: ॥ १७ ॥
ITRANS:
yugāni yuga-dharmāṁś camānaṁ pralaya-kalpayoḥkālasyeśvara-rūpasyagatiṁ viṣṇor mahātmanaḥ
Translation:
Please explain the different ages of universal history, the special qualities of each age, the duration of cosmic maintenance and destruction, and the movement of time, which is the direct representation of the Supreme Soul, the Personality of Godhead, Lord Viṣṇu.