.

If anyone learns by heart the first ten verses of the Surah al-Kahf, he will be protected from the Dajjal.
(Sahih Muslim: Book #004, Hadith #1766)

But it should be noted that “learning by heart” also indicates implementing these aayat on ourselves. And the sufficient proof for this indication is the following hadith about the dream that Prophet Muhammed (pbuh) had:

“He whose head was being crushed with a stone was one who learnt the Quran but never acted on it, and slept ignoring the compulsory prayers.”  
(Sahih Bukhari: Book #21, Hadith #244)



Abud-Darda' (May Allah be pleased with him) reported:

The Messenger of Allah (ﷺ) said:
"Whoever commits to memory the first ten Ayat of the Surat Al-Kahf, will be protected from (the trial of) Ad-Dajjal (Antichrist).

"[Muslim].

In another narration,
the Messenger of Allah (ﷺ) said:
"(Whoever commits to memory) the last ten Ayat of Surat Al-Kahf, he will be protected from (the trial of) Ad-Dajjal (Antichrist).

"وعن أبي الدرداء رضي الله عنه أن رسول الله صلى الله عليه وسلم قال‏:‏ ‏"‏من حفظ عشر آيات من أول سورة الكهف، عصم من الدجال‏"‏ وفي رواية‏:‏ ‏"‏من آخر سورة الكهف‏"‏ ‏(‏‏(‏رواهما مسلم‏)‏‏)

Sunnah.com reference : Book 9, Hadith 31
Arabic/English book reference : Book 9, Hadith 1021
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