Sahih Muslim Book 4, Hadith Number 1766.

Chapter : Excellence of sura Fatiha and concluding verses of surat al-Baqara and exhortation to recite the last two verses of surat al-Baqara.

Abu Darda’ reported Allah’s Apostle (may peace be upon him) as saying: If anyone learns by heart the first ten verses of the Surah Al-Kahf, he will be protected from the Dajjal.