Sayyiduna Abu Darda رضى الله عنه reports that the Prophet ﷺ said: “Whoever memorises the first ten verses of Surah Kahf, will be saved from the trial of Dajjal.” [Muslim, #809]
In some narrations [Muslim, #809; Abu Dawud, #4323], the last 10 verses have been recorded.
As a precaution, one should recite/memorise both sets, the first ten as well as the last ten verses.
Sayyiduna Abu Darda رضى الله عنه reports that the Prophet ﷺ said: “Whoever recites three verses from the beginning of Kahf he is protected from the turmoil of the Dajjal.” [Jami’ Tirmidhi, #2886]
Imam Qurtubi (Allah have mercy on him) has narrated a Hadeeth under the tafseer of Surah Al- Kahf that, whoever reads Surah al-Kahf on Friday will be saved from the fitnah of Dajjal. [Tafseer Qurtubi, Surah Al-Kahf]
Dua for protection from Dajjal
Sayyidah Aishah رضى الله عنها reported that the Messenger of Allah ﷺ would recite the following dua (before the salam) in his salah:
اللَّهُمَّ إِنِّي أَعُوذُ بِكَ مِنْ عَذَابِ الْقَبْرِ، وَأَعُوذُ بِكَ مِنْ فِتْنَةِ الْمَسِيحِ الدَّجَّالِ، وَأَعُوذُ بِكَ مِنْ فِتْنَةِ الْمَحْيَا وَفِتْنَةِ الْمَمَاتِ، اللَّهُمَّ إِنِّي أَعُوذُ بِكَ مِنَ الْمَأْثَمِ وَالْمَغْرَمِ
Allahumma inni a’udhu bika min ‘adhabil Qabr, wa a’udhu bika min fitnatil masiheed dajjal, wa a’udhu bika min fitnatil mahyaa wa fitnatil mamaat. Allahumma inni a’udhu bika minal ma-thami wal maghram
Trans: O Allah I seek you refuge from the punishment of the grave, and from the trial of Dajjal, and the trials of life and death. O Allah I seek your protection form sin and debt.