Al-Bara' bin 'Azib (May Allah be pleased with them) reported:
A man was reciting Surat Al-Kahf, and a horse was tied with two ropes beside him. As he was reciting, a cloud overshadowed him, and as it began to come nearer and nearer, the horse began to trample voilently. The man came to the Messenger of Allah ﷺ in the morning and mentioned the incident to him. He ﷺ said, "That was tranquillity which descended as a result of the recitation of the Qur'an."
[Al-Bukhari and Muslim].
وعن البراء بن عازب رضي الله عنهما قال: كان رجل يقرأ سورة الكهف، وعنده فرس مربوط بشطنين فتغشته سحابة فجعلت تدنو، وجعل فرسه ينفر منها. فلما أصبح أتى النبي صلى الله عليه وسلم ، فذكر له ذلك فقال :
" تلك السكينة تنزلت للقرآن" ((متفق عليه)) .