Srimad-Bhagavatam: Canto 10 - Chapter 1 - Verse 24

Sanskrit:

आसीत्तदष्टाविंशाहमितरेतरमुष्टिभि: ।वज्रनिष्पेषपरुषैरविश्रममहर्निशम् ॥ २४ ॥

ITRANS:

āsīt tad aṣṭā-vimśāhamitaretara-muṣṭibhiḥvajra-niṣpeṣa-paruṣairaviśramam ahar-niśam

Translation:

The fight went on without rest for twenty-eight days, the two opponents striking each other with their fists, which fell like the cracking blows of lightning.

Purport:

Śrīla Viśvanātha Cakravartī points out that the fight continued day and night without intermission.