Surat Al-Kahf - سورة الكهف

ثُمَّ بَعَثْنَاهُمْ لِنَعْلَمَ أَيُّ الْحِزْبَيْنِ أَحْصَىٰ لِمَا لَبِثُوا أَمَدًا

: Then We raised them up (from their sleep), that We might test which of the two parties was best at calculating the time period that they had tarried.