عَنِ الْبَرَاءِ بْنِ عَازِبٍ رَضِيَ اللَّهُ عَنْهُ قَالَ قَرَأَ رَجُلٌ الْكَهْفَ وَفِي الدَّارِ دَابَّةٌ فَجَعَلَتْ تَنْفِرُ فَنَظَرَ فَإِذَا ضَبَابَةٌ أَوْ سَحَابَةٌ قَدْ غَشِيَتْهُ قَالَ فَذُكِرَ ذَلِكَ لِلنَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ فَقَالَ اقْرَأْ فُلَانُ فَإِنَّهَا السَّكِينَةُ تَنَزَّلَتْ عِنْدَ الْقُرْآنِ أَوْ تَنَزَّلَتْ لِلْقُرْآنِ
Sayyiduna Bara bin Azib (may Allah be pleased with him) narrates that a man recited Surah Al-Kahf. In the house where he was reciting, his mount was also tied. The mount began to get restless. He saw that a cloud was overshadowing him. When this was mentioned to the Noble Prophet (peace and blessings be upon him), he said: "O so-and-so! If you had continued reciting, it was tranquility (sakinah) which was descending for the Qur'an."