Quran 18:60 — The Cave (Al-Kahf)

Moses said to his servant, "I will not rest until I reach the point where the two rivers meet, no matter how long it takes."

[18:59] Many a community we annihilated because of their transgressions, we designated a specific time for their annihilation.

[18:61] When they reached the point where they met, they forgot their fish, and it found its way back to the river, sneakily.