قَوْلُهُ تَعَالَى: {هُوَ الَّذِي أَنْزَلَ السَّكِينَةَ فِي قُلُوبِ الْمُؤْمِنِينَ} [الفتح: 4]
A man was reciting Surat Al-Kahf and his horse was tied with two ropes beside him. A cloud came down and spread over that man, and it kept on coming closer and closer to him till his horse started jumping (as if afraid of something). When it was morning, the man came to the Prophet, and told him of that experience. The Prophet ﷺ said, "That was As-Sakina (tranquility) which descended because of (the recitation of) the Qur'an." (Using translation from Bukhārī 5011)
كَانَ رَجُلٌ يَقْرَأُ فِي دَارِهِ سُورَةَ الْكَهْفِ وَإِلَى جَانِبِهِ حِصَانٌ مَرْبُوطٌ حَتَّى تَغَشَّتْهُ سَحَابَةٌ فَجَعَلَتْ تَدْنُو وَتَدْنُو حَتَّى جَعَلَ الْفَرَسُ يَفِرُّ مِنْهَا قَالَ الرَّجُلُ فَعَجِبْتُ لِذَلِكَ فَلَمَّا أَصْبَحَ أَتَى النَّبِيَّ ﷺ فَذَكَرَ لَهُ وَقَصَّ عَلَيْهِ فَقَالَ النَّبِيُّ ﷺ «تِلْكَ السَّكِينَةُ تَنَزَّلَتْ لِلْقُرْآنِ»