hearing Al-Bara say: "There was a man reciting [Surat] Al-Kahf when he saw his riding animal stamping his feet, so he looked and there was something like a shadow or cloud, so he went to the Messenger of Allah ﷺ and mentioned that to him. The Prophet ﷺ said: "That was the tranquility which descends with the Qur'an, or descends because of the Qur'an."  

سَمِعْتُ الْبَرَاءَ بْنَ عَازِبٍ يَقُولُ بَيْنَمَا رَجُلٌ يَقْرَأُ سُورَةَ الْكَهْفِ إِذْ رَأَى دَابَّتَهُ تَرْكُضُ فَنَظَرَ فَإِذَا مِثْلُ الْغَمَامَةِ أَوِ السَّحَابَةِ فَأَتَى رَسُولَ اللَّهِ ﷺ فَذَكَرَ ذَلِكَ لَهُ فَقَالَ النَّبِيُّ ﷺ تِلْكَ السَّكِينَةُ نَزَلَتْ مَعَ الْقُرْآنِ أَوْ نَزَلَتْ عَلَى الْقُرْآنِ وَفِي الْبَابِ عَنْ أُسَيْدِ بْنِ حُضَيْرٍ  

that the Prophet ﷺ said: "Whoever recites three Ayat from the beginning of Al-Kahf he is protected from the turmoil of the Dajjal."  

عَنِ النَّبِيِّ ﷺ قَالَ مَنْ قَرَأَ ثَلاَثَ آيَاتٍ مِنْ أَوَّلِ الْكَهْفِ عُصِمَ مِنْ فِتْنَةِ الدَّجَّالِ حَدَّثَنَا مُحَمَّدُ بْنُ بَشَّارٍ قَالَ حَدَّثَنَا مُعَاذُ بْنُ هِشَامٍ قَالَ حَدَّثَنِي أَبِي عَنْ قَتَادَةَ بِهَذَا الإِسْنَادِ نَحْوَهُ