Quran 18:11 — The Cave (Al-Kahf)

We then sealed their ears in the cave for a predetermined number of years.

[18:10] When the youths took refuge in the cave, they said, "Our Lord, shower us with Your mercy, and bless our affairs with Your guidance."

[18:12] Then we resurrected them to see which of the two parties could count the duration of their stay therein.