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].