مسند أحمد

It was narrated that Aban bin `Uthman said: I heard `Uthman bin `Affan (رضي الله عنه) say: The Messenger of Allah (ﷺ) said: `Whoever says at the beginning of the day or the beginning of the night, ‘In the Name of Allah with Whose name nothing on earth or in heaven can cause harm, and he is the All-Hearing. All-Knowing.` three times, nothing will harm him during that day or that night.”