One verse

Srimad Bhagavatam 12.4.13

12.4.13

तत एकोदकं विश्वं ब्रह्माण्डविवरान्तरम् ॥ १३ ॥

tata ekodakaṁ viśvaṁ brahmāṇḍa-vivarāntaram

tataḥ
then
eka-udakam
a single body of water
viśvam
the universe
brahma-aṇḍa
of the egg of creation
vivara-antaram
within

At that time, the shell of the universe will fill up with water, forming a single cosmic ocean.