A man was reciting Surah al-Kahf with his horse tethered beside him by two ropes when a cloud overshadowed him. It began to circle and draw closer, and his horse started shying away from it. In the morning, he came to the Prophet ﷺ and mentioned what had happened. He said, "That was the tranquility that descended for the Quran."
و حدثنا يحيى بن يحيى أخبرنا أبو خيثمة عن أبي إسحق
كان رجل يقرأ سورة الكهف وعنده فرس مربوط بشطنين فتغشته سحابة فجعلت تدور وتدنو وجعل فرسه ينفر منها فلما أصبح أتى النبي ﷺ فذكر ذلك له فقال تلك السكينة تنزلت للقرآن