The people of Medina were struck with panic while they were with the Prophet ﷺ, and they scattered. I saw Salim, the freed slave of Abu Huzaifa, wrap himself in his garment with his sword and sit in the mosque. When I saw what he did, I did the same. Then the Messenger of Allah ﷺ came out and saw me and Salim, and the people gathered around him.The Messenger of Allah ﷺ said, "People, should your refuge in panic not be Allah and His Messenger? Why did you not do as these two believing men have done?"
فزع الناس بالمدينة مع النبي ﷺ فتفرقوا، فرأيت سالما مولى أبي حذيفة احتبى بسيفه، وجلس في المسجد، فلما رأيت ذلك، فعلت مثل الذي فعل، فخرج رسول الله ﷺ فرآني وسالما وأتى الناس فقال رسول الله ﷺ: يا أيها الناس، ألا مفزعكم إلى الله ورسوله؟ ألا فعلتم كما فعل هذان الرجلان المؤمنان؟
Ahmad (17810) and Nasai in Kubra (8243) narrated it, and Ibn Hibban (7092) graded it sahih, all of them through Musa bin Ali bin Rabah, who said, "I heard my father say, 'I heard Amr bin As say...'" and he related it. Its chain is sahih.Haythami said in Majma (3009), "Ahmad narrated it, and its narrators are the narrators of the Sahih."