Surya Siddhanta
आद्यन्तकालयोर् मध्यः कालो ज्ञेयो +अतिदारुणः। प्रज्वलज् ज्वलनाकारः सर्वकर्मसु गर्हितः ॥
The time (pata) intervening between the moments of the beginning and end is to be looked upon as exceedingly terrible, having the likeness of a consuming fire, forbidden for all works.
english translation