I heard ʿUthman bin ʿAffan ؓ say: The Messenger of Allah ﷺ said: ʿWhoever 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.ʿ three times, nothing will harm him during that day or that night.”
قَالَ رَسُولُ اللهِ ﷺ مَنْ قَالَ فِي أَوَّلِ يَوْمِهِ أَوْ فِي أَوَّلِ لَيْلَتِهِ بِسْمِ اللهِ الَّذِي لَا يَضُرُّ مَعَ اسْمِهِ شَيْءٌ فِي الْأَرْضِ وَلا فِي السَّمَاءِ وَهُوَ السَّمِيعُ الْعَلِيمُ ثَلاثَ مَرَّاتٍ لَمْ يَضُرَّهُ شَيْءٌ فِي ذَلِكَ الْيَوْمِ أَوْ فِي تِلْكَ اللَّيْلَةِ