Pancangikasutta 3.4

3.4

Seyyathāpi, bhikkhave, udakarahado gambhīro ubbhidodako. Tassa nevassa puratthimāya disāya udakassa āyamukhaṃ, na pacchimāya disāya udakassa āyamukhaṃ, na uttarāya disāya udakassa āyamukhaṃ, na dakkhiṇāya disāya udakassa āyamukhaṃ, devo ca kālena kālaṃ sammā dhāraṃ nānuppaveccheyya.

It’s like a deep lake fed by spring water. There’s no inlet to the east, west, north, or south, and the heavens would not properly bestow showers from time to time.