Sahih Muslim – Hadith No : 1891

Al-Bara’ reported that a person was reciting Surat al-Kahf and there was a horse tied with two ropes at his side, a cloud overshadowed him, and as it began to come nearer and nearer his horse began to take fright from it. He went and mentioned that to the Prophet (may peace be upon him) in the morning, and he (the Holy Prophet) said: That was tranquillity which came down at the recitation of the Qur’an.

Hadith In Arabic Text :

وحدثناه يحيى بن حبيب الحارثي، حدثنا خالد بن الحارث، ح وحدثنا عبيد، الله بن معاذ حدثنا أبي قالا، حدثنا شعبة، بهذا الإسناد نحوه وفي حديث خالد بن الحارث قال على راحلة يسير وهو يقرأ سورة الفتح ‏.‏

Chapter : The Book of Prayer (Travellers) – كتاب صلاة المسافرين وقصرها